Bumps on the inside of the lips may be caused by sebaceous gland ectasia, oral herpes simplex, oral ulcers and other causes. 1. Sebaceous gland ectasia: the specific etiology is not clear, may be related to endocrine stimulation during puberty, local stimulation, trauma, etc., may lead to sebaceous gland hyperplasia-like changes, appearing in the lips with small rice grains of goose bumps. 2. Oral herpes simplex: caused by herpes simplex virus infection, manifested in clusters of small blisters, blisters with thin walls and transparent, with the development of localized ulceration, the formation of scabs, the appearance of small rice bumps on the inside of the lips. 3. Oral ulcers: oral breakage, low immunity, bad dietary habits and other factors can cause oral ulcers, which may lead to small rice-like, red bumps on the inside of the lips. It is recommended to go to the hospital in time to improve the examination, and give targeted treatment after the cause is clear. Daily attention to avoid eating too cold, too hot, spicy stimulating food, do not smoke and drink, keep the mouth clean and fresh.