kitten with rash, hair loss, and small bump on nose

[maybe]

My cat is 6 months old and had a little "rash" on the right side of his nose. Now, about 2 months later that is gone but the top of his nose is swollen with one small "lump" on it, there is a small patch of hair loss on his nose and he now has the rash on the left side of his face (where his whiskers are). I took him to a vet and they said it was not in the formation of ringworm and tested negative for cancerous cells under a microscope. My cat used to itch it but now he has not been. Have any ideas as to what this might be?

Thanks Allison