Skin fillers: when, how and where?

Dermal fillers can improve volume, contours, and certain skin depressions, but they are neither a minor procedure nor a universal solution. Their safety depends on proper indication, the chosen product, the treated area, and, above all, the experience of the practitioner administering them. This guide explains when they can be useful, how they are performed, where extra caution is advised, and what signs should not be ignored.

Summary in 60 seconds

• Dermal fillers are injectable substances that are placed in specific tissues to smooth wrinkles, restore volume, improve contours, or correct certain skin depressions.
• The best known are those made of hyaluronic acid, but there are also materials such as calcium hydroxyapatite, poly-L-lactic acid and polymethyl methacrylate microspheres, each with different indications and duration.
• They are primarily used for the face and, in some cases, the hands. They are not intended for «filling» buttocks, breasts, or other body areas for volume enhancement.
• The FDA warns against buying fillers online, self-injecting, or using needle-free devices to inject them.
• Although most immediate effects are mild—swelling, bruising, tenderness—serious complications such as infection, skin necrosis, or visual disturbances can occur if the material accidentally enters a blood vessel.
• Therefore, the most important point is not «which product to use,» but who will be the professional who evaluates and injects it, where they do so, and whether they have adequate training to handle emergencies or complications.

What is it?

A dermal filler is an injectable material used to modify the volume, shape, or surface of certain tissues in a controlled manner. They are also called dermal fillers, injectable implants, or soft tissue fillers.

The word “filler” can be misleading. It’s not about simply “filling” any area that lacks volume. A good procedure requires understanding facial anatomy, the correct depth, the type of product, the skin condition, medical history, and the client’s expectations.

The most commonly used materials include:

• Hyaluronic acid: attracts water and adds volume. It is usually temporary and, in many situations, can be broken down with hyaluronidase if a complication or undesirable result occurs.
• Calcium hydroxyapatite: provides support and may stimulate some tissue remodeling. It does not dissolve with hyaluronidase.
• Poly-L-lactic acid: acts more as a biostimulant; changes appear gradually.
• PMMA: non-absorbable material; its permanence requires particularly careful selection.

The FDA classifies these products as implantable medical devices, and their approval depends on the material, the implantation site, and the specific indication. FDA 2023

What is it for?

Dermal fillers can have both cosmetic and reconstructive uses. In aesthetic medicine, they are primarily used for:

• smooth moderate or deep facial wrinkles
• restore volume to cheeks or areas of structural loss
• Improve the contours of the lips, chin, jawline, or temples, according to the approved product and medical criteria.
• to correct certain depressed scars, such as some acne scars
• improve volume loss on the back of the hands
• to accompany facial rejuvenation plans when the indication is appropriate.

Simply put, fillers can help when the primary issue is volume loss, sagging, creasing, or lack of support . They are not usually the best solution when the main problem is significant sagging, extensive uneven texture, blemishes, pores, visible blood vessels, or wrinkles caused primarily by muscle contraction. In those cases, other options, such as laser treatments, medical peels, biostimulation, surgery, botulinum toxin, or other therapies, may be considered, depending on the individual assessment.

The American Academy of Dermatology describes uses such as restoring fullness to the face, lips, and hands, improving depressions, and smoothing lines, but emphasizes the need for prior specialist medical evaluation. AAD 2026

Dermal fillers are not presented as a universal solution or a «simple» procedure. They are injectable medical implants: they can offer good results in well-selected patients, but they also have limitations, risks, and potential complications. The decision should be made with information, clinical evaluation, and appropriate informed consent.

How does it work?

A simple way to understand it: the face doesn’t age solely due to the skin. Fat, ligaments, bone, muscles, and the way light reflects off the surface also change. A well-chosen filler doesn’t «inflate» the face; it aims to restore specific points of support or soften shadows.

Hyaluronic acid acts as a gel that retains water and adds volume. Calcium hydroxyapatite and poly-L-lactic acid may have a more gradual tissue-stimulating effect. This means that not all fillers work the same way, they don’t last the same amount of time, and they shouldn’t be used in the same areas. FDA 2020

It is also important to distinguish three concepts:

Product: what material is injected.
Plane: at what depth it is placed.
Zone: in which anatomical region it is applied.

The same product may be reasonable in one area and risky or unsuitable in another. Therefore, it’s not advisable to decide on the procedure based on social media, promotions, or third-party photos.

When should you consider dermal fillers?

It can be considered when there is a specific and measurable concern: deep wrinkles, loss of volume, poorly defined contours, depressed scars, or changes that create shadows. It is also considered when the person understands that the result should be proportionate, not permanent, and not always immediate.

It is not recommended to do so due to social pressure, trends, to imitate someone else’s face, to «prevent» without a clear indication, or during an active outbreak of infection, inflamed lesions, or uncontrolled skin disease. The ASDS indicates that before considering fillers, the medical history should be reviewed, the area examined, and treatment postponed if there is an active skin infection. ASDS 2026

Special caution should also be exercised if there is a history of recurrent cold sores, clotting disorders, anticoagulant use, significant allergies, autoimmune diseases, previous procedures with unknown products, or unrealistic expectations. A prior consultation is not a formality; it is a central part of safety.

Where can they be applied for?

The responsible answer is: it depends on the product, the anatomy, the indication, and local regulations .

In general, fillers are used in areas such as nasolabial folds, cheeks, lips, chin, some perioral lines, certain scars, and the backs of the hands. In the United States, the FDA describes approved uses in adults for moderate to severe wrinkles and folds, augmentation of the lips, cheeks, chin, and hands, as well as certain contour corrections, scars, and HIV-associated facial lipoatrophy. FDA 2023

However, there are areas of particular risk or where many products are not approved for use, such as the nose, glabella (between the eyebrows), forehead, the area around the eyes, and the neck. Some new indications may exist for specific products, but that doesn’t mean any filler is safe in any area. The FDA also warns against using fillers for breast augmentation, buttock augmentation, foot augmentation, or injection into bone, tendons, ligaments, or muscle. FDA 2023

A word of caution: if the plan sounds like “filling in a lot”, “doing it at home”, “using a product bought online” or “applying to large body areas”, it is not a safe procedure.

What to expect? Before / during / after

Before

A medical consultation is required, including a review of medical history, skin assessment, analysis of asymmetries, clinical photographs if applicable, medication review, and explanation of alternative treatments. Risks, expected duration, possibility of touch-ups, costs, warning signs, and a management plan in case of complications should also be discussed.

The AAD recommends asking if the filler is approved for that use, how long it lasts, what adverse effects might occur, and how much experience the practitioner has with that product. AAD 2026

During

The procedure is performed in a clinical setting, with appropriate hygiene measures and equipment. Topical or local anesthesia may be used depending on the area. The injection can be administered with a needle or cannula, depending on the case. Patients typically experience pressure, mild pricking, or temporary discomfort.

It should not be performed in hotel rooms, private homes, hair salons, social events, or any location without medical facilities. It also should not be done with needle-free devices marketed as “safer”; the FDA warns that these devices are not approved for injecting fillers and can cause serious injury. FDA 2023

After

It’s common to notice swelling, redness, tenderness, or bruising. In many cases, these changes improve within a few days; some areas, such as the lips, may become more swollen. The result may look different at the end of the session than it does two weeks later.

The most common adverse effects are usually local and transient, but not all pain or discoloration is normal. Subsequent clinical review allows differentiation between expected outcomes and complications.

Aftercare

After a dermal filler, the instructions should come from the professional who performed the procedure, because they depend on the area, the product and the patient’s history.

As a general guideline, it is usually recommended to avoid manipulating or pressing the area without medical advice, avoid exposure to intense heat immediately afterward, avoid vigorous exercise on the same day or as otherwise directed by a doctor, avoid self-medicating, and monitor for changes in color, pain, or visual disturbances. If a follow-up appointment was recommended, it is advisable to attend even if the result seems satisfactory.

Intense massage, attempts to «adjust» the product at home, or dissolving or correcting a filler on your own should be avoided. Hyaluronidase, when needed for hyaluronic acid fillers, should be used by trained medical personnel with clinical judgment. Kroumpouzos 2024

Expected vs. unexpected effects

Expected effects

They may appear:

• mild or moderate swelling
• bruises
• sensitivity
• localized redness
• feeling of tension
• minor initial irregularities
• transient asymmetry due to inflammation

These changes usually improve gradually. Even so, the evolution depends on the region and the product.

Unexpected effects

They require prompt contact with a healthcare professional and medical evaluation:

• intense or progressive pain
• pale, bluish, grayish, or net-patterned skin
• blisters, wounds, or early scabs
• fever, pus, or spreading redness
• significant loss of sensitivity
• painful nodules or persistent inflammation
• any visual impairment
• severe headache or neurological symptoms.

The most feared complication is accidental injection into a blood vessel, which can reduce blood flow to the skin or, rarely, compromise vision or the nervous system (Site 2019 ).

Warning signs: when to seek emergency care

Seek immediate medical attention if any of these signs appear after a filler procedure:

• Intense pain that is not related to a normal discomfort.
• sudden change in color: paleness, purplish spots, gray skin, or a reticulated pattern
• blurred vision, vision loss, eye pain, or difficulty moving the eye
• facial weakness, difficulty speaking, confusion, or neurological symptoms
• fever, purulent discharge, or rapidly worsening inflammation
• appearance of ulcers, blisters or black spots
• marked swelling of the lips, tongue, eyelids, or difficulty breathing

These situations should not be left unattended without medical guidance. Adverse event management guidelines emphasize the early recognition and urgent treatment of vascular occlusion, especially when the filler is hyaluronic acid. Jones 2021

How to choose a professional or center

Choosing wisely reduces risks, though it doesn’t eliminate them. A good center doesn’t promise perfect results or minimize complications. It explains, documents, and has a plan.

Checklist of questions before performing the procedure

1. Who will perform the evaluation and who will administer the injection?
2. What is your medical training and specific experience with fillers?
3. What product will be used and is it approved for that area or indication?
4. Does the product come sealed, labeled, and traceable?
5. What alternatives are there if I’m not a good candidate?
6. Which side effects are common and which are rare but serious?
7. What plan do you have if a vascular occlusion, infection, or inflammatory reaction occurs?
8. Do they have hyaluronidase if hyaluronic acid fillers are used?
9. What should I do if I experience pain, changes in color, or visual disturbances?
10. Will there be informed consent and follow-up?

The FDA recommends working with dermatologists or plastic surgeons and avoiding over-the-counter products or self-administered injections. The AAD also warns against receiving fillers in non-medical settings, such as salons, homes, or spas, without proper supervision. FDA 2023, AAD 2026

Frequently Asked Questions

Are dermal fillers the same as botulinum toxin?

• No. Botulinum toxin relaxes specific muscles to smooth dynamic wrinkles. Fillers provide volume, support, or contour correction. In some plans, they can be combined, but they are not interchangeable.

How long do they last?

• It depends on the material, the area, the technique, and individual metabolism. Hyaluronic acid can last from approximately several months to over a year, depending on the product and area; calcium hydroxylapatite and poly-L-lactic acid may last longer in some cases. The FDA indicates approximate durations for each material, but these should not be taken as an individual guarantee. FDA 2020

Can hyaluronic acid be removed?

• In many situations, hyaluronic acid fillers can be treated with hyaluronidase. This does not mean they are “risk-free,” nor that every correction will be immediate or perfect. Other materials do not dissolve with hyaluronidase and may be more difficult to remove. Kroumpouzos 2024

Is it normal to feel swollen?

• Yes, some swelling can be normal, especially in the lips. What is not normal is severe pain, a worrying change in color, visual disturbances, fever, discharge, or rapid worsening.

Can I get fillers if I have a cold sore?

• It depends. A history of cold sores must be reported before the procedure, as some injections can reactivate them. The practitioner may decide to postpone or prescribe preventative medical treatment depending on the case. Injections should not be administered if there is an active infection.

Are “hyaluron pens” or needle-free devices safe?

• They should not be considered a safe alternative. The FDA and AAD warn that needle-free devices for injecting fillers do not allow for adequate control of product placement and have been associated with serious injuries. AAD 2022

What result should I be looking for?

• A sensible result respects proportions, anatomy, and facial movement. The goal shouldn’t be to erase every line or completely change the face, but rather to reasonably correct a specific concern. With fillers, more product doesn’t necessarily mean a better result.

Bibliography and sources

• US Food and Drug Administration. Dermal Fillers (Soft Tissue Fillers) . Silver Spring: FDA; 2023.
• US Food and Drug Administration. FDA-Approved Dermal Fillers . Silver Spring: FDA; 2020.
• US Food and Drug Administration. Dermal Filler Do’s and Don’ts for Wrinkles, Lips and More . Silver Spring: FDA; 2023.
• American Academy of Dermatology Association. Fillers: Overview . Rosemont: AAD; 2026.
• American Academy of Dermatology Association. Fillers: Preparation . Rosemont: AAD; 2026.
• American Academy of Dermatology Association. Fillers: FAQs . Rosemont: AAD; 2026.
• American Academy of Dermatology Association. Needle-free fillers: The risks you need to know about . Rosemont: AAD; 2022.
• American Society for Dermatologic Surgery. Dermal Fillers . Schaumburg: ASDS; 2026.
• Jones DH, Fitzgerald R, Cox SE, Butterwick K, Murad MH, Humphrey S, et al. Preventing and Treating Adverse Events of Injectable Fillers: Evidence-Based Recommendations From the American Society for Dermatologic Surgery Multidisciplinary Task Force . Dermatol Surg. 2021;47(2):214-226. doi:10.1097/DSS.0000000000002921.
• Sito G, Manzoni V, Sommariva R. Vascular Complications after Facial Filler Injection: A Literature Review and Meta-analysis . J Clin Aesthet Dermatol. 2019;12(6):E65-E72.
• Kroumpouzos G, Treacy P. Hyaluronidase for Dermal Filler Complications: Review of Applications and Dosage Recommendations . JMIR Dermatol. 2024;7:e50403. doi:10.2196/50403.
• Colon J, Mirkin S, Hardigan P, Elias M, Jacobs RJ. Adverse Events Reported From Hyaluronic Acid Dermal Filler Injections to the Facial Region: A Systematic Review and Meta-Analysis . Cureus. 2023;15(4):e37620. doi:10.7759/cureus.37620.