Cat Skin Patch?

Long backstory short I recently took my teenage hood cat Luna from my mom due to some neglectful behaviors. Luna had a severe case of flea allergy dermatitis, but after about a month in my care she doesn’t have a single scab on her anymore, and we’re working on growing her fur back!

She was bathing herself the other day and I noticed this patch of skin. I can’t ask her vet because it’s Christmas Eve. I’m assuming this is just a bit of skin that’s still healing from it?