The jaw is actually the part of the body where lymph nodes are very prone to enlargement, and the first thing that comes to mind when something hard suddenly appears in this location may be a localized lymph node enlargement. For further clarification, it is recommended that the patient still needs to go to the hospital for an ultrasound examination. Because most of the enlarged lymph nodes are caused by inflammatory reactions, other causes cannot be ruled out. In addition to detecting lymph nodes, ultrasonography can also identify localized subcutaneous occupations, such as localized lipomas, localized fibromas or sebaceous cysts. Usually, ultrasound can make a better judgment, and patients do not need to be nervous.