A small ball moving when touched under the chin may be enlarged submandibular lymph nodes, lipoma and sebaceous cysts. 1. Enlarged submandibular lymph nodes: when patients suffer from tonsillitis, mumps, oral inflammation and other diseases, due to the presence of inflammation, localized superficial lymph nodes can be enlarged and pressure pain occurs. The enlarged lymph nodes have certain mobility, no adhesion with surrounding tissues, clear boundary, and fluctuating sensation when touching. 2. Lipoma: Lipoma can appear in any part of human body, small tumors usually do not cause pain, mainly manifested as subcutaneous movable swelling, soft texture, slow growth. 3. Sebaceous cysts: the jaw area is rich in sebaceous glands, and when the follicular opening is blocked, it may also cause sebaceous cysts formed by the gathering of cortex in the local area. Usually manifested as a smooth surface, clear boundaries, often adhered to the skin, but the base can be moved. It is recommended that when patients have the symptom of touching a small ball on the chin that moves, they should go to the hospital in time to do relevant examinations to clarify the cause of the disease.