oh good lord. Bloat!

my understanding of 'bloat' is that it is a secondary symptom. Something is going on that is preventing the frog from controlling its own fluids, and it blows up like a balloon.

if this is bacterial in nature, then you need antibiotics and a new environment for recovery.
if it's organ damage, then the damage is done and there isn't really anything to do.

go see a vet, get his opinion and, perhaps, antibiotics.

lots of web information on 'frog bloat'.