We actually still have no idea, over $500 in vet bills and not much has changed. Whatever she has is immune to both of the antibiotics we have tried - the culture didn't show anything - the next step would be to put a camera somewhere? I'm not quite sure, but the vet said that it probably won't show much either. She eats for me every week, drinks, doesn't do anything abnormal except wheeze a little when she gets out of her cage. I have another snake I'm taking to the vet next week so I'll see what the vet thinks we should do about the boa then.
I'll post an update after the vet, I'll ask him some more questions and get some things cleared up.
Thanks for asking about her, she is a sweet snake