Lumps in the joint between the gums and the cheeks may be caused by pericoronitis of the mandibular wisdom teeth, mumps, and periapical inflammation. 1.Pericoronitis of mandibular wisdom teeth: . The eruption position of wisdom teeth in the jaw is blocked, causing inflammation and infection, leading to infection of the occlusal space, resulting in a lump at the connection between the gums and the cheek, which may be accompanied by pain. 2. Mumps: Viral infection caused by autoimmune deficiency leads to mumps, which may be accompanied by swelling and pain in the area where the gums connect with the cheeks. 3. Periapical inflammation: The inflammation of the dental pulp attacks the periapical tissues, and the inflammation spreads to the surrounding tissues, causing lumps in the connection between the gums and the cheeks, accompanied by swelling and pain in the gums. It is recommended that the patient consult a doctor in a timely manner, under the guidance of the doctor to improve the examination to clarify the diagnosis, and carry out the correct treatment. Daily attention to keep the mouth clean and fresh, drink more water in moderation, avoid eating spicy and stimulating food.