Did you apply any flea or tick treatment in the last couple days? One of ours got a dose of Revolution for ear mites ( not sure how he got them as he is strictly indoors) and 2 days after the treatment he had a bald spot like that. Vet recommended Neosporin and when that didn't help he got a shot of vitamin B and a light dose of steroids. It healed fine after that.

Thank you for your input!! He has not had any flea and tick treatment. What a strange reaction for your cat! And to get mites inside is strange, too.

ringworm would normally be scaly and very circular, although it can start out looking like a red itchy dot before it progresses, but from the pic it doesn't have a typical ringworm look about it. I would just try a skin cleaner a few times daily and see if that clears it up (I've found epi-otic which is an ear cleaner/skin cleaner to be quite good for healing up random sore spots/bald patches quite quickly on dogs in the past). From what I can see it looks like a sore in a bald patch so the baldness may be from rubbing or scratching. If I were to describe ringworm I've seen (years ago) it looks like scaly skin with a pronounced raised border around it in a circular lesion

Thanks for your input! That's really relieving to hear that description of ringworm. So... I've been using this on the spot for the last couple of days. I've heard really good things about it, and got it for a little cut that he had recently. Hopefully this will help to clear things up. If anyone else has any ideas, I'm grateful to hear them. Thank you!!

Looks like a Hot Spot. Home remedy for dogs (at least) - mist with Listerine.

Google the term for photos and treatments.

Thanks for the idea! I hope it is just that. That would be really nice. The pics on Google look so red! I think the stuff I'm spraying on him is supposed to be for those.

I googled your Vetericyn and it is one of many candidates for treating Hot Spots.

Thank you! Yay!