The problem looks to me, to be in your temps. Kick up the ambient temperature to around 78-80F. They don't thermo-regulate, so you'll need to keep the ambient temperature around that area. Don't let it creep too high, or the frog may stop eating, or this problem may repeat itself again. Watch misting daily, as moisture may allow for fungi, and mold build up and growth. Something that could hurt your frog. As well as that; I've noticed when they're kept damp, or wet, they develop a few problems including skin lesions, and sores. Just pick up an accurite Thermometer/hydrometer, and monitor the humidity levels.

What type of bedding are you using?