In most cases, swollen lymph nodes behind the ear have little effect on the body because they are often caused by infections in the surrounding tissues, such as parotid gland infections, dental infections, especially wisdom tooth infections, and so on. The swollen lymph nodes can gradually subside if you go to the hospital for routine blood tests, C-reactive protein and local ultrasound, and then drink more warm water and give anti-inflammatory drugs or anti-viral drugs according to the test results. However, if the enlarged lymph nodes are abnormal, or if conservative treatment is ineffective, it is necessary to completely exclude whether there are blood system diseases, or lymphoma, or even lymph node metastasis of malignant tumor, etc. This requires further investigation of tumor markers and lymph node biopsy to clarify the cause, and according to the results, corresponding treatment is given, and if necessary, surgical resection is also required.