I took her to the exotic specialist vet on Tuesday because her sneezing hadn't cleared up, she was losing her appetite (or ability) to eat even soft food, and she was losing weight. She's seen this vet before, back when she had tooth problems over Christmas. He's very knowledgeable.
He prescribed her chloramphenicol, which is apparently a good antibiotic for anaerobic bacteria, such as those that might infect the root of a tooth. However, either the antibiotic or her illness has caused her to stop eating all together. She won't even eat a Cheerio, which have been a favorite treat.
They're squeezing us in at the vet tomorrow for general anesthesia and tooth evaluation... but if they don't find anything, there's really nothing else to be done for her.