suspected ringworm

Hey all, I've found a scab on my piggie's back (left hand side just after her front leg) and not sure what it is. She's had a few ringworm breakouts in the last few months, but has been in the clear for ~3 months now. I've noticed she's itching this spot a fair bit & also has dandruff...

I just visited the vet for some other issues and he was given antibiotics for a UTI. I told them my concerns (this was before i discovered the scab) and I think they only checked that. In a wellness exam aren't they supposed to exam the whole pig? Now I'm worried they didn't even check the other...

On Friday I noticed that one of my guinea pig’s fur on the nose had gone slightly yellow and a little crusty (as can be seen in the first two photos). His breathing sounded just fine and his eyes showed no signs of cloudiness, discharge, watering etc, he has been eating and behaving as normal...