Pimples under the chin may be acne, folliculitis and so on. It is considered to be related to long-term bad habits, poor hygiene, genetic factors, excessive sebum secretion, and blockage of the follicular opening. 1. Acne: The onset of acne is related to androgen levels, genetic factors, excessive sebum secretion from sebaceous glands, and abnormal keratinization of follicular sebaceous gland ducts. Localized excessive sebum secretion and proliferation of Propionibacterium acnes lead to blockage of the follicular opening, and acne may appear under the chin. 2. Folliculitis: inflammation caused by bacterial or fungal infection, mainly related to the decline in immune function, poor hygiene habits, etc., is also the main reason for acne under the chin. It is recommended to go to the dermatology department of the hospital to get a clear diagnosis of acne under the chin, and treat it with the doctor’s advice.