A lump under the ear can be the result of the following diseases: first, it is a lipoma that occurs under the skin and will manifest itself as a localized mass that gradually increases in size and also becomes painful. The examination will reveal a tender mass with clear borders and good mobility, which can be surgically removed. Secondly, if the cyst occurs in the sebaceous gland or if the cyst becomes infected, the patient will also experience localized pain. If a significant infection is formed, an abscess will also be formed and the patient will also have fever. Early limited patients can choose surgery to remove the lesion completely, while abscesses formed need to be surgically incised and drained and require intermittent drug changes after surgery to promote healing. The treatment can also be combined with anti-infection treatment during the treatment period, and oral amoxicillin capsules can be taken. In addition, pay attention to local hygiene to avoid aggravation of infection.