Inclusion Criteria:  Adult (20 years or older) Progressive keloid lesion that is bilaterally symmetric, mandibular area, anterior chest or suprapubic area, for example At least 4 cm in length Repeated or uncontrolled recurrence, and unendurable symptoms with poor response to conservative modalities Valid written informed consent provided for surgery and trial inclusion  Exclusion Criteria:  Allergy to botulinum toxin Previous botulinum toxin injection at the lesion within 6 months before enrollment Myasthenia gravis Focal infection signs Pregnant or breastfeeding woman