All hope is not lost yet. I have nursed some rescued emaciated WC BPs back to health when all was left was literally skin and bones (each rib was visibly distinct from the next through the skin). I also recommend a vet visit to a qualified reptile vet. Even if she has been treated for parasites before, a treatment of metronidazole can help get her gut tract back on course, and may even be an appetite stimulant. Either way, you will likely need to tube feed her for a while to get some nutrients back into her. Ask your Doc for the correct supplies and food (I've used a few different animal diet products). Don't try to do all this blind though, qualified vets are a life saver when it comes to issues like this. Don't give up, they will make it if you do things right. Let us know how they are doing in the coming weeks.

-Evan