The appearance of white granules on the skin of the mouth may be caused by sebaceous gland ectasia, lipitis, herpes of the mouth and lips, hand, foot and mouth disease. 1. Sebaceous ectasia: mostly occurring after puberty, manifested by the appearance of small white or yellowish granules and pimples of pinpoint size on the lips, usually without special treatment. 2. Lipitis: a collective term for inflammatory diseases of the lips, inflammatory stimuli can cause small white granular blisters or edematous plaques on the lips, but also accompanied by dry lips, peeling and other symptoms. 3. herpes orofacialis: related to herpes simplex virus infection, can be manifested as white granules, small blisters on the lips and the surrounding skin, can also be accompanied by weakness, sore throat, fever and other symptoms. 4. Hand, foot and mouth disease: related to enterovirus infection, belongs to the infectious diseases, mostly seen in the hands, feet, mouth, buttocks and other parts of the body, can cause small white particles on the lips, pimples and other symptoms. If white particles appear on the skin of the mouth and are accompanied by obvious discomfort, it is recommended to go to a regular hospital to find out the cause and actively cooperate with the doctor’s treatment, so as not to delay the condition.