Please help :(((

I don't know what is on my cats skin. She doesn't go outside and these red crusty patches of skin just started coming up. Me and my mom have started cleaning one last week and another came up and I just noticed it today. She is about 12 years old and she's never had any medial issues. Please help

Could be flea bites or even ant bites??  I'm not sure, but I'd at least call the vet to make sure it's not anything more serious.
 

I would say flea allergy dermatitis. It's possible for people to bring fleas in from the inside, where they will live in your flooring, and then for them to start feeding off your pets. Get a good flea regimen (do NOT use Hartz, BioSpot, or any over the counter flea med or collar) and put some diatomaceous earth or borax down on your carpet to kill the fleas (make sure kitty is out of the room)  and leave it there at least several hours before you vacuum it up. You may cut up a flea collar and put it in your vacuum bag/canister to help kill any fleas that are vacuumed up.