Fatty grains may refer to milia. Milia on the arms can usually be removed in the hospital by picking them out with a sterile needle, or by laser treatment.
Corns are retention cysts that originate in the epidermis or epithelium of the appendages, and can appear as yellowish-white, firm papules following trauma, dermatologic conditions, or medications. They can be treated by visiting a hospital, sterilizing the area, and using a needle to puncture the epidermis and remove the small, yellowish-white granules inside. They can also be removed by other treatments, such as carbon dioxide laser therapy.
Patients with milia on their arms can consult a professional doctor in the hospital and use the right way to get rid of them under the doctor’s guidance, and it is not recommended to blindly treat them on your own.