Consider sebaceous cysts or lymph nodes, where the sebaceous cysts are on the skin and may have a redness. Lymph nodes are located under the skin and can be classified as congenital or acquired (inflammatory or tumorigenic) according to the duration of the disease, and can be specifically identified according to the following methods: 1. Because of the cystic contents, it cannot be cured by applying medicine alone, but can be cured by removing it after local anesthesia. No treatment has no effect on the overall health. 2. Lymph nodes are located under the skin and can be palpated. Depending on their nature, they can also be hard and can be pushed or not. According to the course of the disease, they are divided into the following three types: (1) congenital, usually found after birth or shortly after birth, and do not progress or grow slightly with physical development. (2) Inflammatory, which is found later in life, has a shorter course, progresses rapidly, and can increase rapidly in size within a few days, may be painful, or may have no conscious symptoms, and is associated with ear-related inflammatory diseases. (3) Tumorigenic disease has a long course and can last from several months to several years, with a slow increase in size and generally no conscious symptoms. Because the lymph nodes are located under the skin, the diagnosis needs to be confirmed with ultrasound findings or lymph node biopsy results. Most bumps behind the ear are benign or inflammatory and there is no need to panic, but a clear diagnosis is recommended before treatment.