I have a White's Tree Frog that at one point had an extremely swollen left front leg. I took her to the vet and they did testing on her, took out some of the liquid, even x-rayed her, and it ended up that she had a poor lymphatic return (the white blood cells weren't circulating through her body correctly). At first I thought that she might have some other disease where all the legs start swelling, but after none others did, that's when I took her to a vet. The only way you can get medication to cure that though is from the vet, and they also have to get the correct doseage. As far as throwing up mucus...is she shedding maybe? Sometimes that can look like they're throwing up, but I'm not sure what you do and don't know about the frogs so I may be wrong. Take her to a vet though, and suggest a poor lymphatic return. My vet was nice and didn't charge me as much for the frog's testing/medication because of the size. Good luck with that!