Thanks for using Petco Pet Education Center, formerly Petcoach! I do recommend all abnormal growths be evaluated by a veterinarian to determine if they are benign (non-cancerous) or not. Skin growths can be due to a variety of reasons, including allergies, infection, allergies, warts, or true tumors. What type of growth it is typically can be evaluated by a needle sample by your veterinarian, and then a treatment plan can be made, if needed. Good luck!