He looks very very thin, I would take him to a vet asap. That is severly underweight, you should probably force feed at this point, I didn't realize how underweight he was.

Force feed is somewhat simple, but stressful so be careful.

Take the frog in one hand, and a business/credit card in the other. Carefully slip the card into the mouth, and lightly pry the bottom jaw down, and insert a cricket into his mouth, and let the jaw go, and he should do the rest. Force feed around 3 crickets and put him back into the enclosure and put some crickets in the bowl.