Closed mouth acne on the chin is mainly acne, and repeated acne may be caused by sebaceous glands, endocrine disorders, and inadequate cleansing. 1. Sebaceous glands: The sebaceous glands are innately developed and have a strong secretion function, resulting in excessive sebaceous gland secretion, which causes pore clogging and acne. 2. Endocrine disorders: endocrine disorders caused by various reasons, such as late nights, emotional abnormalities, etc., causing excessive secretion of androgens and increased secretion of oil in the skin. 3. Inadequate cleansing: Inadequate daily cleansing causes dirt to remain in the pores, a large accumulation of oil, and mite infections. Acne should pay attention to the skin clean, regulate the daily routine, timely medical treatment, in the doctor’s guidance symptomatic treatment.