According to the vet, she probably scratched her ear and nicked a blood vessel, causing a hematoma. They drained her ear, but it seems to be (fortunately slowly) refilling. We're planning to schedule another appointment for Monday, when they said they could basically sew her ear together to prevent it from happening again. I would have guessed they would go for cauterization, but apparently not.
edit; She's also quite underweight (apparently she's six pounds). I thought that was because she's getting old (she's approaching fifteen years) but the vet says she just needs to eat more. We got her some wet food to entice her appetite.
Re: getting her to eat
Our 12-year-old kitty was recently diagnosed with kidney disease, and on top of that she had a kidney infection. After several weeks of antibiotics the kidney infection has cleared up, but we've been struggling with getting her to eat enough, especially while she was really sick.
Finding the right wet food has really helped. She can only eat kidney-approved foods right now so our options are more limited. Turns out she does not care for the paté style wet foods but she LOVES the Royal Canin options with "little slivers." I think she prefers that she can pick up the bits in her mouth rather than licking a clump of meat lol. The Royal Canin kidney diet options are specifically designed to be appealing to cats who might have a limited appetite, and I can definitely vouch for its effectiveness with our girl.
I know you're not needing kidney-friendly foods for your girl, but my point is, if she doesn't like the first wet food you try, they have different options and maybe she'll prefer another type. So experimenting might help.
At one point we needed an appetite stimulant for our girl, so that's an option too. The vet gave us a transdermal medication that you rub on your cat's ear (so they can't lick or rub it off before it gets absorbed.) That might be an option for you, although probably just in the good ear right now 🙂 The appetite stimulant REALLY helped us when our girl was in the midst of her infection. She went from basically not eating anything to being so hungry that she was purring while eating her food cause she was so happy 🥹
Originally we used the appetite stimulant every day, but it's not necessarily good for long-term use in cats with kidney disease, so we're trying to figure out the minimum dose to keep her eating. She got a half dose about four days ago, which kicked up her appetite. And I think getting used to eating more food again is relatively self-sustaining for her, because she's still eating more all these days later. So yeah, I can also vouch for the effectiveness of the appetite stimulant.
The brand name is Mirataz
All good information, thank you for the recommendations! Hopefully your cat stays as healthy as she can.