I wouldn't worry about that. They are notorious for going on fasts. As long as you keep everything in the tank the way it should be, i.e. humidity, temperature, etc. and he looks healthy and hasn't started losing weight then he should be fine. Just keep trying to feed him on the normal schedule that you have been and make sure the water dish is always about 3/4 full for him to drink or soak in and to keep humidity up a bit. He should eventually eat again when he's hungry. Hope that helps.