Complications of Limitations of Botulinum Toxin in Facial Aesthetic Practice: A Comprehensive Review

AbstractBotulinum toxin has emerged as one of the most widely utilized minimally invasive agents in facial aesthetic practice because of its predictable, reversible, and effective outcomes in facial rejuvenation. Its applications have expanded across dermatology, plastic surgery, and oral and maxillofacial surgery for the management of dynamic wrinkles and selected functional disorders. However, the increasing popularity of botulinum toxin procedures has also led to greater recognition of associated complications and treatment limitations. Most adverse effects reported in the literature are technique-dependent rather than product-related, emphasizing the importance of anatomical knowledge, careful patient selection, and precise injection techniques. Common complications include injection-site pain, edema, erythema, ecchymosis,eyelid and brow ptosis, facial asymmetry, dysphagia, dysarthria, drooling, and impaired mastication. Aesthetic concerns such as frozen facial expression and compensatory muscle hyperactivity may also negatively affect patient satisfaction. Although systemic complications are rare, immunogenicity and treatment resistance following repeated injections remain important concerns. Additional limitations include the temporary duration of action, requirement for repeated treatments, and limited efficacy in static wrinkles. Safe and successful outcomes depend on evidence-based practice, conservative dosing, and continuous professional training.