My cat has a spot about the size of a fifty cent piece on her lower back

My cat has a spot about the size of a fifty cent piece on her lower back about a half inch from her tail. This looks like scab of some sort but, i'm not for sure. It feels really rough and her hair is sorted matted up in it. It doesn't bleed or have an odor. My cat is a little on the hefty side and i'm not sure if she can clean this area as well as her other body parts.

What should I do?

it coukld just be a scab from a scratch...especially possible if the cat is an outdoor cat...

but if it looks like it might be a mole or something....Take your cat to the vet.

B.C