Painful underarm dermatomas may be due to localized tissue necrosis. Axillary dermatomas are actually soft fibrous tumors of the skin, similar to small grains of rice adhering to the surface of the skin, usually connected by a thin tip, and normally do not cause pain. If an axillary dermatome is painful, it may be due to prolonged friction and irritation, resulting in ischemia and necrosis of the dermatome, which can lead to inflammation and pain. In most cases, no special treatment is needed, but in cases of necrosis and enlargement, surgery or laser treatment should be considered to improve the symptoms. There may be other reasons for the pain of axillary dermatomes, it is recommended that patients go to the hospital in time to improve the examination, follow the doctor’s instructions to take standardized treatment, do not ignore the disease, so as not to delay the treatment of the condition.