Hard lumps appearing under the baby’s skin are considered to be lipoma, epidermoid cyst, sebaceous cyst, which can be temporarily observed, treated with medication and surgery to relieve. 1. Lipoma: this is a common benign soft tissue tumor, usually grows slowly, most of them have no clinical symptoms and do not need special treatment, if the tumor is relatively large, it can be surgically removed. 2. Epidermoid cysts: Epidermoid cysts are cysts containing keratin in the dermis, commonly found in the face and trunk, most patients do not have clinical symptoms and do not need special treatment, if the tumor grows rapidly, it can be surgically removed. 3. Sebaceous cysts: these are cysts formed by the gradual accumulation of sebum. If infection occurs, erythromycin ointment and fusidic acid cream can be applied to control the infection, and the infection can be removed by surgery. The hard lumps under the skin, you should go to the hospital in a timely manner, by the doctor to clarify the cause of standardized treatment, such as the need for medication, you should follow the doctor’s instructions to use.