The causes of chin acne in boys may be related to high androgen levels, proliferation of Propionibacterium acnes, and abnormal keratinization of follicular sebaceous gland ducts. 1. High androgen levels: High androgen levels can make sebaceous glands function more vigorously and secrete large amounts of oil, which may lead to chin acne. 2. Proliferation of Propionibacterium acnes: If Propionibacterium acnes proliferates on the chin, it may cause inflammatory reactions and acne. 3. Abnormal keratinization of follicular sebaceous gland ducts: If the follicular opening at the chin is over-keratinized, it can block the ducts, preventing the normal discharge of shed epithelial cells and sebum, which can form pimples. It is recommended that boys with chin acne go to the hospital in a timely manner to clarify the cause, and if treatment is needed, it should be standardized under the guidance of the doctor.