Awww, thanks everyone! I feel a right fool, it's a skin infection with some swollen glands. The vet said I'd caught it really early, which is rare as it's only a wee patch -pyoderma.
He sometimes gets a wee matted bit in his armpti, so I noticed it when I was paying close attantion grooming him. He's on tenkorex tabs for a week, and return if it's not cleared up.
I feel a bit of a fool, I panicked though.
Thanks for all the support, you are so kind
Shona xx