When Too Much Filler Affects Facial Expression

A 2023 study from clinics in the Netherlands and the United Kingdom looked at 28 people whose smile felt or looked unnatural after hyaluronic acid filler in the midface. Using ultrasound to find exactly where the filler sat, the clinicians dissolved targeted pockets with hyaluronidase, and every treated side was reported to improve. The study suggests that filler in the wrong layer, not just too much of it, may affect how the face moves.

Why this was studied

"Overfilled" is often used to describe a face that looks puffy or heavy, especially in the cheeks. These researchers focused on a specific, less discussed problem: filler that changes facial expression. Patients described a smile that looked stiff, wider than before or simply not their own.

The authors suspected that filler sitting in certain tissue layers could restrict the muscles that lift the corners of the mouth during smiling. If so, finding and removing that specific filler might restore a more natural expression without dissolving everything.

What the researchers did

This was a retrospective study: the team looked back at the records of 28 consecutive patients referred to them, 26 women and 2 men with an average age of about 46. Both sides of the face were treated in each person, giving 56 treated sides. On average, their original filler had been placed nearly two years earlier, though some had been treated only a month before and some more than a decade before. People with signs of inflammation were excluded.

High-frequency ultrasound was used to locate hyaluronic acid filler in the midface. The clinicians then injected hyaluronidase directly into the filler pockets they could see on screen. About a third of patients needed a second session.

What they found

Ultrasound showed filler in every patient, often in a fibrous layer between the superficial and deep fat of the cheek. In about a quarter of sides, filler had spread across several layers rather than staying in one place. Most patients reported that the problem began immediately after their original treatment.

After targeted dissolving, the researchers reported immediate improvement on all treated sides, judged by the patients and the treating physician. Measurements taken from photographs during a full smile showed that the corners of the mouth sat somewhat higher and farther apart after treatment, which the authors interpreted as freer smile movement.

The authors also looked at lines at the outer corners of the eyes during smiling and reported a small change, though the paper gives conflicting figures on whether that change was statistically meaningful. The paper did not report complications or long-term follow-up, so we do not know how many people kept their improvement or later chose to have filler again.

How strong is this evidence?

This is a small, uncontrolled study of referred patients, and it has several limits:

• There was no comparison group, such as people treated without ultrasound guidance.
• Improvement was recorded as a simple yes or no, not with a validated scale.
• Details of the original filler, including product, amount and technique, were mostly unknown.
• Some numbers in the paper are inconsistent between sections, and two authors have a financial interest in ultrasound education.

The study is useful because it describes a real problem and a plausible approach in a reasonable number of people. It does not prove that ultrasound-guided dissolving works better than other approaches, or that it works for everyone.

What it means for you

A natural-looking result is not only about the amount of filler but also about where it is placed and how the face moves afterward. A face can look fine at rest yet seem stiff or unfamiliar when smiling. If you notice that, it is worth raising with your clinician rather than adding more filler to balance things out. Our article on avoiding the overfilled look discusses planning that helps prevent this.

If you already have filler that feels wrong, dissolving is often possible, because hyaluronic acid responds to hyaluronidase. Ultrasound can help some clinicians see where filler sits, especially when the history is unclear, although it is not available everywhere and is not required for every case. Our article on dissolving filler explains the process, including skin testing, swelling and the possibility of needing more than one session.

Collagen-stimulating fillers such as calcium hydroxylapatite or poly-L-lactic acid (PLLA) do not dissolve with hyaluronidase. Knowing what was injected before, and bringing any records you have, helps your clinician plan.

Dissolving is not right for everyone. People with allergy to hyaluronidase, active infection in the area, or who are pregnant should discuss alternatives. Side effects can include swelling, bruising, temporary hollowness and, rarely, allergic reactions.

Questions to ask at your consultation

• Does my smile or expression look changed by my current filler?
• Do you know what product and depth were used before?
• Would partial dissolving help, or is full dissolving better for me?
• How long should I wait after dissolving before considering any new treatment?

Frequently asked questions

Can filler really change how I smile?

This study suggests it can in some people, likely when filler sits in a layer that affects how the cheek tissues glide during expression. It is not common, but it is recognized.

Will dissolving make my face look older?

Removing filler can bring back some of the hollowing that was originally treated. For many people, a more natural expression is worth that trade-off, and future treatment can be planned more conservatively if desired.

Do I need an ultrasound to have filler dissolved?

Not necessarily. Many dissolving treatments are done without imaging. Ultrasound can be helpful when filler location is uncertain or results have been disappointing.

If something about your filler result feels off, HealthPark Medical Aesthetics can assess your face at rest and in motion and talk through whether dissolving, waiting or no further treatment is the right choice.

Source

Schelke L, Harris S, Cartier H, Alfertshofer M, Doestzada M, Cotofana S, Velthuis PJ. Treating facial overfilled syndrome with impaired facial expression: presenting clinical experience with ultrasound imaging. Journal of Cosmetic Dermatology, 2023. Read the study