Jaw usually refers to the lower jaw. A small bag under the lower jaw can be examined in the dermatology, general surgery, ear, nose and throat departments of the hospital. 1. Dermatology: Small bags in the lower jaw are most common with dermatologic diseases. You can first go to the dermatology department of the hospital for examination to clarify whether it is related to folliculitis, acne and other diseases. 2. General Surgery: If there is a small bag in the jaw, if it is a subcutaneous swelling or localized secretion, you can go to the general surgery department of the hospital for examination to clarify whether it is related to thyroid, superficial swelling, anterior cervical fistula and so on. 3. Otorhinolaryngology: if the small bag in the jaw is accompanied by dysphagia, abnormal voice, etc., you can go to the otorhinolaryngology department of the hospital for examination, to clarify whether it is related to the pharyngeal swelling. To summarize, there are many reasons for the appearance of localized pouches, it is recommended to go to the dermatology department of the hospital for examination, to exclude skin diseases, and then go to the relevant departments for further examination to clarify the diagnosis under the advice of the doctor.