I had the exact thing happen to mine. Even with adequate heat, humidity, no external stressors, etc. I have noticed that my frill doesn't do well when fed rodents heavily. You may consider getting a colony of roaches. The blood panel on my frill showed elevated white blood cell counts, showing some type of internal infection. I gave him sub-cutaneous injections of antibiotics for 10 days or so and he popped right out of it. He looked REALLY bad. I almost had him put to sleep at one point. Keep up with supportive care and if I can remember what drug he recieved I will pass that along to you.

Good Luck!