Hot water should not be applied to swollen lymph nodes behind the ear. Swollen lymph nodes behind the ear are usually caused by inflammation, tumor lymph node metastasis or lymphoma. Lymph nodes are immune organs, and if lymphadenitis occurs, the lymph nodes will be enlarged and can even be felt on the body surface. Hot compresses do not work to eliminate the swelling of lymph nodes. If the lymph nodes are enlarged due to inflammation, anti-infection treatment, such as oral antibiotics, needs to be given. If the lymph node enlargement is caused by tumor metastasis, it is necessary to further check the primary lesion of the tumor in other parts of the body, and then further treat the primary tumor, such as surgery, radiotherapy and chemotherapy. If the lymph node enlargement is caused by lymphoma, it is necessary to determine the type of lymphoma, and then choose the appropriate chemotherapy and radiotherapy programs. Patients with enlarged lymph nodes behind the ear should actively seek medical treatment, make a clear diagnosis after systematic examination, and follow the doctor’s instructions to standardize the use of medication and treatment.