Big and small faces may be caused by unilateral biting muscle hypertrophy due to daily chewing habit, which can be adjusted by slimming injection, but if it is caused by developmental abnormality that leads to hemifacial atrophy, slimming injection is generally ineffective. Usually, people with large and small faces caused by unilateral biting muscle hypertrophy due to daily chewing habits can be adjusted by face thinning injection. If the developmental abnormality triggers half-sided facial atrophy, it is generally not possible to adjust with face slimming injection. Face slimming injection is to inject botulinum toxin into the biting muscle to make part of the muscle atrophy and become smaller, so as to achieve the purpose of adjusting the size of the face. This method has the advantages of minimally invasive and simple process, but the clinicological effect will disappear with the metabolism of botulinum toxin, and generally need to be re-injected in 6-8 months. It should be noted that for ingredient allergy, myasthenia gravis, multiple sclerosis, pregnancy, breastfeeding and other people can not use thinning needle to adjust the size of the face. The size of the face does not affect the health, if you think it affects the aesthetics, it is recommended that the applicant go to a regular hospital, follow the advice of a specialist physician to choose the appropriate treatment program.