Grease grains on the skin may be caused by causes such as cornu rashes or closed mouth acne. 1. Corns: benign skin swellings or retention cysts, manifested as pinhead-sized bumps on the skin, often white or yellowish-white pimples, smooth surface, easy to occur around the eyes, can be extruded sebaceous material, can lead to the phenomenon of the skin with oil particles. 2. Closed mouth acne: a chronic skin disease that occurs in the hair follicles sebaceous glands, mostly due to sebaceous gland openings blocked, sebum content can not be discharged, in the local accumulation, and the gradual formation of white keratin material pimples, can also lead to the appearance of facial skin oil particles. The appearance of oil particles, generally do not need special treatment, but if accompanied by other symptoms, it is recommended to timely to the hospital, to clarify the cause of the disease, as soon as possible treatment.