The causes of jawline acne may be sebum overproduction, abnormal keratinization of follicular sebaceous gland ducts, and Propionibacterium acnes infection. 1. Excessive sebum secretion: The androgen level is higher during puberty. Under the action of androgen, the sebaceous glands function vigorously and secrete a large amount of oil, causing acne along the jawline. 2. Abnormal keratinization of follicular sebaceous gland ducts: Excessive keratinization of the follicular opening can block the ducts, affecting the normal discharge of shed epithelial cells and sebum, which can lead to jawline acne. 3. Propionibacterium acnes infection: If you are infected with Propionibacterium acnes, it can break down sebum and produce inflammatory factors, causing an inflammatory reaction that can lead to jawline acne. It is recommended that people with jawline acne go to the hospital in a timely manner to clarify the cause of the problem and under the guidance of the doctor to carry out standardized treatment.