Update:
The wound area has been spreading since it was found. The spreading has slowed down. Below are new photos:
My students and I had just sprayed her medicine on, which is why she has her collar on and why the wound looks wet. Normally, it is now dry, which is a small step forward. One student is holding his hand over her eyes, to discourage her from running away during the medicine-applying and photo-taking. The indentation near her rump is where fur was cut away for the old wound, which sadly today had a new little fresh part. No idea why.
A closer shot of the affected area.
I have been taking her to a vet almost every day for a week and a half. Yesterday I took her to a new vet that my students had found for me, an office that was larger and had a lab and x-ray machine. Unfortunately, I was not impressed with that office. The head vet couldn't even get Qingqing out of her cage, and once I got her out, he didn't hold her. The other vet can get her out quicker than I can, and holds her when he treats her. The vet took scrapings from the sore spot and examined them in a room. I didn't see what kind of equipment they had back there. My students had trouble translating what he said, being unfamiliar with medical terminology. The general idea was that the skin problem was bacterial and fungal. He sold me a bottle of medicine, then said Qingqing had to keep her collar on for three days. He also took an x-ray of her, but she was awake for it and it didn't look good quality to me. He couldn't really tell what the lump in her jaw was. When I got home, I didn't put on the new medicine, because I didn't want to collar her for three days. I know my critter. She would be so sad that she might die if she had to wear that thing for three days.
I went back to the old doctor today and showed him the lab report and x-ray from the other office. He couldn't tell anything from the x-ray and said to continue with his medicine. I'm going to follow his advice. I trust him more than I do the new vet who wouldn't even hold my rabbit.
Though the skin problem seems to be slowly getting better, or at least it's not getting worse, she continues to have other problems:
1) She is losing weight, even though she still eats. I presume that she's not eating as much as before, though it seems like she's eating almost as much. I can feel her bones when I pet her, and especially when I'm holding her down. I've had her weighed at the vet's and she is indeed losing. She was at 3.75 kilos the first time we went to the vet about two weeks ago, a week later she was at 3.38, then a few days ago at 3.14 then today at 3.11.
2) She is not active at all. When she has the collar on, she stays in her room, either sitting still, occasionally crouching, sometimes eating. When the collar is off, she is still often laying down and occ. crouching, but sometimes coming out of her room to hop around the apartment. I noticed today that she prefered staying by the heater. I wonder if losing the weight has made her sensitive to cold. (It's a radiator heater, inside a wooden cabinet thing. She can't get hurt by it.) Tell me, when a rabbit crouches, does that mean pain or fear or something else?
3) Her poops have gotten small again. They were the size of BBs several days ago, but went back to almost their normal size. Last night and today they were smaller than BBs.
4) I was able to catch her urine in a bowl, so now I know there's no blood in it. Apparently the odd smell and reddish color are caused by the mixture of poop and pee. Does this mean anything? It started a couple of weeks ago, coincidentally (?) after the vet had me clean the wound with a dark red liquid that was something like iodine, I guess. After I stopped using this liquid, the reddish mixture in her cage pan continued, to this day.
If she continues to lose weight, I don't see how she can survive. I don't like the thought, but I'm prepared for it. I'm also thinking that there's more going on that skin problems. The vet says it takes a long time for skin problems to clear up. I need to ask if animals lose weight with skin problems. As has been said here, the lump in her jaw may be an influence in her ills, and there may be something else going wrong.
As always, I appreciate any comments and advice. If you don't feel comfortable offering advice on the open forum, please PM me.