I think my guinea pig has mites...?

I have 3 guinea pigs and I seem to have picked 3 with the most problems in the world. The problem with this is, I live in Knoxville, TN and there is literally no exotic vet to be found. I've called every vet within a 50 mile radius and no one will treat them (so please.. if anyone lives here and knows of an exotic vet, PLEASE let me know.) Anyway, he seems to have mites or some other skin condition because he is plucking out the hair on both of his thighs. He has one or two scabs, nothing too severe.. but, I have no idea what to do in order to help him. He bites and scratches at it all the time.