Closed mouth on the face is mainly due to endocrine disorders, clogged pores and bad dietary habits, Propionibacterium acnes infection and so on. 1. Endocrine disorders: patients in puberty or long-term late-night endocrine disorders, skin pores oil secretion is exuberant, resulting in pore blockage caused by closed mouth. 2. Pore blockage: patients use unqualified cosmetics and skin care products for a long time, or make-up cleaning is not in place, resulting in pore blockage caused by occlusion. 3. Bad dietary habits: patients eat irritating food and fried food for a long time, such as hot pot, fried skewers, barbecue, etc., which irritate the skin resulting in closed mouth. 4. Propionibacterium acnes infection: As Propionibacterium acnes resides in the skin and hair follicles, a large number of reproduction stimulates the hair follicles and sebaceous gland ducts to appear abnormal keratinization and hyperplasia, resulting in sebum elimination obstacles to form closed mouth. Patients need to go to the hospital, follow the doctor’s instructions for treatment, the application of drugs need to strictly follow the doctor’s instructions.