This evening after getting fitted for a test pair of bifocal contacts, I went up to skritch her and check on her. I've been a bit disturbed by the fact that she only leaves our bed to eat and use the litterbox, and last night she seemed to have a lot of trouble getting back up onto the bed, even using the ottoman as an intermediate step. When I got upstairs, I noticed blood on the blanket. I figured that she'd popped a stitch - one drop of blood in saliva looks like you've slaughtered a pig. Then she got up.
Her hip was a mass of blood and pus. Apparently he scored one good bite during that first cat fight, and it abscessed. Which explains the continued disturbance - he could smell the infection, and she felt like crap. It also explains why she wasn't moving around - I'm sure it hurt more and more as the pressure built.
I called the emergency vet, and they are of the opinion it can wait until tomorrow with my vet. Then I called a friend who is a vet tech, and who knows me and my cats. She gave me some good advice that would make me feel better. So I clipped the fur away and put hot, wet compresses on it for an hour or so to clean out the yuck - and it's yucky. Icky and oozy and *stinky.* But I'm sure it actually feels better now that it's open. I'm trying to convince her to lay on some old, clean towels. vynehorn suggested that I slip a heating pad under them, and she seems to like that. Meanwhile, it oozed all over the white quilt my mother made for me, and the dry-clean only wool/silk blanket.
Tomorrow morning I will call my vet as soon as they open and tell them we're coming in. I have no idea if they'll need to keep her overnight. I hope not.