Here’s a consult for all you vets out there. First let me tell you that I have an appointment to take my dog to the vet tomorrow but thought I’d get some opinions.
History is a 9 y/o F spayed Tibetan with one day of biting and scratching at her posterior and dragging her butt on the ground. Very uncomfortable appearing. No GI symptoms or urinary problems. Here’s the pic

Another one. No history since it’s obvious.