Hi there, Ringworm sucks man! I have had ponies with ringworm and I have treated them the same as mudfever. Wash in betadine and remove the lumpy skin/scabs and wash again with betadine for 5 days. Its a fungus and is stiil alive and protected under the scab so is important to remove it. Yes it will look red and angry underneath but keep going. I wash covers with bleach and then rinse again and leave em swingin in the sun. Sunlight helps to heal the scabs so may pay to uncover horse for awhile. You will know its gone when skin returns to normal colour and you can see hair growing back. BE CAREFUL as ringworm is contagious and you can get it too!
Always wash your hands thoroughly after treating. Good luck.