Maybe it's some stuffed animal or something that she took some pieces off. Or something else, like a piece of clothing or maybe pieces of a bone or one one of her treats???? I would definitely give her a bath and check her skin very carefully. Check her pads on her feet, her ears, butt, teeth, everything. For me, that's when I give my girls a really good going-over, during their baths, and when I am brushing them, right after. Good luck!