I took him in to the vet the next morning. The prolapse had worsened again overnight. The vet examined him while I was at work..he left a message on the answering machine saying that the problem would have been rectified by the warm water bath, but he continued to strain to defecate. Apparently he had ingested another frog that was too large to digest properly, and was passing undigested bits. The vet euthanized him for me.