Hey Charlie … I agree with KZ a trip back to vet to check might be wise…
I’ve had many unpleasant dealings with ringworm in kittens in particular ..
Ring worm can take up to 3-4 weeks to appear as lesions on the skin so yes a vet checking Guts two weeks ago would have no way of knowing if ringworm is present.. It’s normally only suspected when the bald patches or lesions appear and then all cats in contact with that cat are assumed to have been in contact with the fungus and will either treat with sulphur baths ( now a very convenient treatment for the humans and smells!) or there are oral fungal meds that are very expensive .. But most people treat with an over the counter anti fungal ointment… (Always check with your vet with the over the counter meds)
Also a lot of strains of the ringworm fungus show up under a black light so if you happen to have one you could check with that in a dark room..
So if it is ringworm and lesions are only showing now then it could take another 3 weeks for the lesions to show on your skin.. Some strains of the ringworm fungus are weaker than other but all are highly contagious to all humans and other animals.. A friend of mine adopted a kitten a couple of months ago and discovered 3 weeks later bald patches and started treating her for them but because the kitten slept in her dogs beds and had contact with the dogs they also developed ringworm it took a few weeks for her to get on top of the treatment of all her animals , herself and to properly clean all effected bedding..
It’s not the end of the world and it’s an unfortunate park of adopting kittens there in your home for weeks before any signs show -and at that stage everyone in contact had been exposed..
Fingers crossed it isn’t ringworm but even if it is it’s not the end of the world just a nuisance ..