Blister?

[aquariumart]

I have an azureus female that has quickly developed what looks like a milky blister on her leg. Unfortunately her mate is calling and I can't get a good picture. She is five+ years old and the largest azureus I have seen. I recently redid their tank but they have been acting normal and eating. Any advice please. There are no local vets that will even look at her.
Thanks