Recurrent hard acne on the chin is considered to be related to acne and folliculitis, and its causes include diet, lifestyle habits, endocrine and other aspects. 1. Diet: If the patient likes to eat spicy or sweet food, it may stimulate the sebaceous glands to secrete more oil, and then the local area is easy to merge with the infection of acne bacillus, which will lead to the appearance of redness, swelling, pain and obvious pimples. 2. Lifestyle habits: If patients always stay up late or do not pay attention to skin cleansing, resulting in increased secretion or residue of facial oil, it will block the pores, thus causing inflammation of local hair follicles and the emergence of hard pimples, accompanied by obvious tenderness. 3. Endocrine: For patients with high work or study pressure and polycystic ovary syndrome, endocrine disorders can lead to an increase in oil secretion from the sebaceous glands, which can block the local pores and lead to the occurrence of acne. For patients with recurring hard acne on the chin, it may be related to the above factors. If the symptoms continue to be unrelieved, it is recommended that the patient go to the dermatology department of a regular hospital and be actively treated under the guidance of the doctor.