Hi there!
Its best to see your vet before starting treatment, to make sure you are treating with the right thing. I have treated mild fungal issues before using surolan ear drops as a topical treatment (prescribed by piggy savvy vet). The pig in question was a new addition At 12 weeks old, where she had fungal patches below one eye, beside the nose and on the edge of her ears. I applied the surolan drops as a cream onto the affected areas twice a day and it cleared up very quickly. I binned any toys that couldnt be washed (cardboard boxes/tunnels, wooden chew toys, willow balls etc) and made sure i cleaned and distinfected everything the piggy touched every other day, a full cage clean and washed my hands after touching any of the pigs or their vicinity. I had a heart failure piggy that would be at a higher risk of catching the ringworm, but she didnt in the end with strict hygiene protocols.
Your vet will best advice you on what the skin complaint is, and how best to treat it. Remove all unwashable items from his cage, and distinfect, rinse and dry his cage and belongings regularly with F10 if you can get a hold of it.
Wishing him a speedy recovery!