Asymmetry of the left and right faces may be caused by congenital developmental problems, bad habits, trauma or diseases. 1. Congenital developmental problems: due to congenital maldevelopment, localized muscle deficiency, developmental asymmetry of bones, muscles and fat of the left and right faces, which leads to asymmetry of the left and right faces. 2. Bad habits: Bad habits such as chewing food unilaterally for a long time, resulting in a more developed chewing muscle on one side, or infants and young children habitually sleeping on one side, may lead to asymmetry of the left and right faces. 3. Trauma or disease: It is also possible that the face can not be repaired by trauma or suffer from some diseases, such as inflammation, tumors, joint diseases, etc., which may lead to the asymmetry of the left and right faces. If it is caused by bad habits, you need to remove the bad habits in time, the disease should be treated for the original disease in time, and if necessary, you can be corrected by injections and fillers.