A lump below the left ear after a cold in a girl may be due to enlarged lymph nodes, sebaceous cyst behind the ear and other diseases, which can be treated with medication and surgery. 1. Enlarged lymph nodes: Infection around the lymphatic tissues is manifested as enlarged lymph nodes, which leads to a lump below the left ear after a girl has a cold. If the infection is bacterial, it can be treated with cefixime, cefuroxime and other drugs as prescribed by the doctor. 2. Behind-the-ear sebaceous cysts: If parents do not clean behind the ear, the back of the head and neck and other hidden parts of the child in daily life, there may be sweat or dust clogging the pores, resulting in a lump behind the girl’s left ear after a cold, if necessary, need to be surgically removed. In addition to medical treatment, daily care needs to be strengthened, such as a light diet, avoid spicy, stimulating food, so as not to aggravate the occurrence of infection. There may be other reasons for a lump below the left ear after a girl’s cold, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.