Lesch-Nyhan syndrome (LNS) is a rare X-linked recessive disorder involving purine metabolism caused by the congenital absence of hypoxanthine guanine phosphoribosyl transferase. A characteristic feature of LNS is the appearance of intractable self-injurious behavior, usually in the form of severe lip and finger biting. The mechanism behind this severe self-mutilating behavior is unknown, and is one of the main challenges in the management of this condition. We here report the case of a 30-year-old man with a confirmed diagnosis of LNS who was successfully treated for self-mutilation of his lips with repeated botulinum toxin A (BTX-A) injections in the facial perioral muscles. Our findings suggest that treatment with BTX-A helped reduce self-abusive behavior in this patient. Our case illustrates that BTX-A injections can be a useful therapeutic approach in patients with self-abusive behavior.