Correction of Iatrogenic Facial Asymmetry Caused by Botulinum Toxin Using Contralateral Injection: A Case Report

Abstract Facial symmetry is a key determinant of aesthetic harmony and psychosocial well-being. Iatrogenic asymmetry is a recognized complication of botulinum toxin injections and may cause both functional and emotional distress. Contralateral botulinum toxin adjustment is an accepted corrective strategy, but few case reports have documented its use for toxin-induced asymmetry with photographic evidence. A 44-year-old woman developed facial asymmetry after cosmetic botulinum toxin injections. She presented with upward deviation of left oral commissure and midface both at rest and during speech, causing psychosocial discomfort. Dynamic assessment showed relative overactivity of the left facial muscles compared with the weakened right side. Targeted contralateral injections of botulinum toxin type A were delivered into the left zygomaticus minor, depressor anguli oris, and mentalis muscles (14 units). At the two-week follow-up, the patient showed substantial restoration of facial balance with improved commissure position and symmetry. Post-treatment photographs confirmed correction. No adverse events were observed. Contralateral botulinum toxin injection is a possible minimally invasive method for correcting toxin-induced asymmetry.