We're OK! At least the vet believes that we are. He was going to go ahead and do a skin scraping only because of her history, but Bella just wouldn't cooperate. She does have a bad ear infection (which is the other reason that I took her in), so we are on antibiotics, low dose steroids, and ear drops. If it is demodex (which he said that if he really thought it was then he would admit her, sedate her, and get a skin scraping), then steroids are bad for that, so it will definitely flair up.
Sounds like I'm just a little paranoid. Better to be safe than sorry!
Thanks for the responses.