I just got this guinea pig yesterday for my daughter from it's previous owner who could no longer take care of him. He posted such cute pictures of him and never mentioned anything being wrong with the little guy, once in my home I noticed this patch of missing fur and it looks scaly / scabby. I called the previous owner right away and he told me not to worry about it, it's just a birth mark. I am not stupid I know that's a lie! I was wondering if anyone on here has seen this before and knows what it is? I would like to know if I could treat it myself instead of going to the vet. Any advice would help thank you!