She needs to see a vet familiar with treating herps, that's your only option. If there is not one available, there is a vet who is able to help via pics and detailed descriptions of the problems. His name is Dr. Frye and maybe you can find his email if you search the forum.
if I understand correctly, you had her housed with your greys? But not anymore? You do know it is not advisable to mix frog species because of the risk of toxicity?
What size enclosure do you have her in now?
It's also not necessary to flood the enclosure with misting. White's don't require very high humidity, in fact it could cause bacterial infections and respiratory illness.
Have you read this? Frog Forum - White's Tree Frog Care - Litoria caerulea
I found this care article very helpful when I first got my white's.
Aside form those things, you should seek the advice of a vet. The bump could be any number of things, and very treatable.
Good luck, and don't let this little girl down.