A lump on the jaw is commonly caused by hair follicle infection, body surface swelling, lymph node enlargement, submandibular gland lesions, etc. The details are as follows: 1. Hair follicle infection: when there is a local infection, the swelling can be touched and requires a visit to the hospital’s dermatology department, which usually requires topical medication; 2. Body surface swelling: such as sebaceous cysts, lipomas, fibroids, etc., which requires a visit to the hospital’s general surgery department or head and neck surgery department Lymph node enlargement: there are many causes, such as bacterial infection, viral infection, tuberculosis infection, autoimmune system disease, blood system disease, and even lymph node metastasis of malignant tumor, etc.; 4. Submandibular gland lesions: such as submandibular gland infection or submandibular gland swelling, which requires local ultrasound or CT for clarification. During the examination, do not drink drinks containing alcohol and do not eat spicy food.