You can get a micronozale spray from amazon for like 10 bucks, it's SUPER effective on ringworm and other skin fungii. Also works on humans and is the active ingredient in many foot sprays.
https://www.amazon.com/Davis-MSP04-Miconazole-Spray-Pets/dp/B00DHPDDFO/ref=sr_1_10?dchild=1&keywords=micronazole+spray+pets&qid=1589675158&sr=8-10