There can be multiple causes for this and one of them can be ringworm. I would get this checked by a vet because you do not want ringworm to spread.

Do you have another cat?

I’ve had these on some of my cats when they are a little stressed or off. I think it’s a fungus (Ringworm? or is that still a different thing?) and the immune system usually keeps it at bay, and it can appear when the cat is unhappy or overwhelmed with something. Were there recent changes for your cat that they might not have liked?

Only if it jumps over on you.