The reason for a little swelling under the ear may be the inflammatory swelling of the local lymph nodes under the ear, which may be related to infectious inflammation, malignant neoplastic lesions, sebaceous cysts, parotid masses and other causes, as follows: 1. Infectious inflammation: often related to infectious inflammation in the surrounding skin area, acute infectious inflammatory factors of the respiratory tract, the lymph nodes may show significant pressure pain performance; 2. Malignant neoplastic lesions: some patients may show painless lymph node enlargement, which requires further detailed examination for the presence of malignant neoplastic lesions in the nasal cavity, sinuses, nasopharynx, and pharynx; 3. Sebaceous cysts: localized sebaceous cysts may appear under the ears, which may also lead to local swelling; 4. Parotid masses: some patients may also have parotid masses, which require further Detailed examination is needed to help clarify the diagnosis.