Unexpected Botulinum Toxin Effect on Neck Rejuvenation After a Jawline Lifting Procedure: A Case Report.

Aging of the platysma muscle significantly contributes to the loss of mandibular contour definition and the vertical platysmal bands aspect, negatively affecting the neck appearance. Botulinum toxin has been widely used for facial rejuvenation, including jawline lifting. We described the case of a 51-year-old woman who underwent lower-face neuromodulator treatment with prabotulinumtoxinA (Nabota®, Daewoong, Seoul, South Korea). Nine superficial injection points per hemiface were applied along the mandibular and submandibular regions. Three-dimensional stereophotogrammetry (LifeViz® Mini, QuantifiCare, Biot, France) was performed before treatment and 15 days post-procedure to quantify the soft tissue displacement and volumetric changes. Clinical evaluation demonstrated a visible reduction of platysmal bands during muscle activation and improved mandibular contour definition. The 3D analysis revealed a volume reduction of 2.4 mL in the right upper neck region and 6.32 mL along the lateral cervical area. No adverse events were reported. These findings suggest a distal functional effect on the platysma muscle, highlighting a potentially safer and lower-dose approach for neck rejuvenation. Further studies are required to validate these results.