Small granular papules in the mouth may be caused by ectopic sebaceous glands, lichen planus, etc., as follows. 1. Ectopic sebaceous glands: also known as seborrhea, usually located in the cheek and lip red, for the ectopic sebaceous glands, yellowish particles, can occur in clusters or scattered, the surface is smooth, and there are no conscious symptoms. 2. lichen planus: a chronic inflammatory disease of the oral mucosa, lesions manifested as small papules connected to a linear white, grayish-white pattern, can occur in any part of the oral mucosa, including the tongue, gums, vestibule, lips, palate, the floor of the mouth and so on. There may be other reasons for the growth of small granular papules in the oral cavity, it is recommended to go to the hospital in time, after clarifying the cause of the disease early targeted treatment.