Changes under the ear are mostly seen in sebaceous cysts, inflammation of lymph nodes behind the ear, parapharyngeal gap tumors and so on. 1. Sebaceous cysts: mainly due to the gradual accumulation of sebum behind the ear to form cysts, is a common benign skin changes, usually does not cause obvious discomfort, but if secondary bacterial infection, may lead to local redness, swelling and hot pain. 2. Inflammation of lymph nodes behind the ear: It may be caused by inflammation of lymph nodes behind the ear, mostly due to nearby inflammatory infections, such as pharyngitis, otitis media, etc., which may lead to lymph node enlargement and inflammation. 3. Parapharyngeal space tumor: for example, cervical nerve sheath tumor, neurofibroma, neurofibromatosis, hemangioma, lipoma and fibroma can show this feature, and it may gradually aggravate with the condition, resulting in enlargement below the ear. Enlargement under the ear may also be caused by parotitis, parotid tumor, etc. You should go to the hospital in time and cooperate with the doctor for examination and treatment.