Generally, ringworm in dogs will not heal on its own, because ringworm is a highly contagious skin disease and may worsen the symptoms if not treated in time. Although dog ringworm is not fatal, it can be very uncomfortable for your dog, and if left untreated, your dog may be infected with other diseases. If the symptoms are not serious, you only need to spray medicine on the area with ringworm. If the symptoms are severe, you need to give the dog a medicated bath or take it to the hospital for treatment. You should pay attention to maintaining hygiene at ordinary times, provide your dog with nutrition to enhance its resistance, and let your dog get more sun.