There is a hard pimple under the chin. If it is acne, it can be treated with topical medication such as retinoic acid cream; if it is a sebaceous cyst, it can be surgically removed; and if it is a viral wart, it can be treated with physical therapy, topical medication and other measures. 1. Acne: related to exuberant secretion of androgen, hyperkeratosis of sebaceous gland ducts of hair follicles and propagation of Propionibacterium acnes, it can be treated with topical medication such as retinoic acid cream, adapalene gel, and fusidic acid cream, etc. For serious cases, minocycline and isotretinoin soft capsules can be taken. 2. sebaceous cysts: local sebaceous gland conduit blockage secretion silt formation of cystic structure, can also lead to a hard acne under the chin, can be surgically removed cysts. 3. Viral warts: These are benign growths of the skin caused by human papillomavirus infection, and can also cause a hard pimple under the chin. You can take physical treatment measures such as laser freezing, and you can also apply imiquimod cream, fluorouracil cream and other medications. There is a hard acne under the chin, there may be other reasons, you need to go to the hospital in time to check, clear the cause of the disease, under the guidance of the doctor to standardize the treatment, the above drugs need to be used in accordance with the doctor’s instructions.