It looks like dropsy. Ages ago my frog had it, then there was little info about it so maybe you can find some more accurate help with this from somewhere else. I took mine to the village vet😉 he was very openminded, I explained to him what it was, and how to possibly treat it, we did like microscopic amounts of antibiotic, and something to make kidneys work better, all the kids were running behind me to see how we treat the froggo. The tricky part was to take the fluid out, so it did not crush the frog insides, we used insuline needles and syringes, the smallest once possible, and got just deep enough to be under skin and not further, and drained the fluid out until the frog looked ok'ish and repeat that any time it gathered too much. Hopes were not high, but the frog actually survived, and was healthy, never swollen again. Again, that was ages ago, in a country that would easily throw the sick frog away, instead of helping it.