Face slimming is essentially the use of botulinum toxin injections to treat an enlarged bite muscle. Women, who are beautiful with an oval face shape, often require plastic surgery due to hypertrophy at the jawline. More than 90% of these patients are accompanied by benign bite hypertrophy and wish to reduce it at the same time. Due to the difficulty in grasping the amount of muscle excision and the depth of muscle excision during mandibular angle surgery, not only is the result unsatisfactory, but it also tends to increase the chance of bleeding, hematoma, and infection, resulting in serious complications such as asymmetry on both sides of the face, dental closure, and longer-term muscle spasm. In 1994, Smyth et al. reported the experience of using botulinum toxin type A to treat bilateral bite hypertrophy, which was considered as a revolutionary new method. Botulinum toxin injections atrophy and reduce the size of the bite muscle through a denervation effect, allowing for more complete treatment. Botulinum toxin is not as scary as its name suggests. Many beauty places call it biological wrinkle removal, or genetic wrinkle removal, in order to remove the fear. It is very commonly used in neurology, ophthalmology, plastic and cosmetic surgery because of its nerve blocking effects. The current dose used is only one percent of its maximum safe dose, so it is very safe. In 1986, Mr. and Mrs. Carruther in Canada accidentally discovered its good wrinkle-reducing effect when they treated eyelid spasm with Botulinum toxin. The Carruthers became the inventors and pioneers of this technology. Botulinum toxin treatment for bite muscle hypertrophy is usually done by selecting 1 or 2 injection sites per side. The injection should be done as slowly as possible, and there is no need for local massage or other special treatment after the injection, as normal chewing movements can gradually spread the drug in the muscle tissue. Botulinum toxin type A can be injected into the bite muscle within 1 month and the atrophy of the bite muscle and the change of the face shape can be observed. As a muscle injection, Botox has no significant side effects and offers more advantages than traditional surgical methods. Local adverse effects after Botulinum toxin type A injection include excessive weakness of the occlusal muscles and corresponding manifestations due to the spread of Botulinum toxin to the adjacent muscle tissue, and these clinical manifestations are related to the injection site and the dose of Botulinum toxin injected. Individual patients have been found to have fever, discomfort, and fatigue after botulinum toxin injection. These clinical manifestations are usually transient and disappear on their own within a few weeks. The effect of botulinum toxin injection usually lasts for about one year, and then there is a possibility of recurrence, but it can be injected again.