hello before using medications consult dermatologist Wash the rash with soap and water. Spread an antifungal cream over the rash. Apply the cream beyond the edge of the rash. antifungal cream or powder that contains terbinafine, miconazole, or clotrimazole. In rare cases, ringworm of the skin causes large areas of blisters. If your ringworm forms blisters, you can use compresses (such as Burow's compress, which you can buy without a prescription) to soothe and dry out the blisters.