The growth of a meatball at the corner of the mouth may be related to boils, common warts, sebaceous cysts and other causes. 1. Boils: the hair follicles at the corners of the mouth are infected by bacteria and other pathogens, causing local inflammatory reactions and skin swellings, which may be accompanied by itching and pain. 2. common warts: human papilloma virus infection of the skin and mucous membranes at the corners of the mouth, resulting in benign growths at the corners of the mouth, manifested as round bumps. 3. sebaceous cysts: sebaceous gland secretions can not be normally discharged from the mouth of the gland, resulting in the accumulation of sebum in the mouth of the gland to form cysts, which can be manifested as similar to meatballs. It is recommended to go to the hospital in time to clarify the cause of the disease and carry out standardized treatment under the guidance of the doctor.