There is a melleri-specific forum on Yahoo! you should check in with. But, a few things right off the bat:
Melleri often go through a "honeymoon period" when they eat everything and are very active. But, once the stress and privation of their capture, shipping, and poor care catch up with them they tend to go downhill fast. You are seeing the delayed effects of all this stress, and he's (no way to know the sex for certain) losing the ability to hide his problems that have been there all along. The cage is much too small (he's damaged his feet and snout trying to get out). If his TOES are turning black he has infections resulting from the torn claws that may need oral antibiotics to treat. If only the claw or the broken off surface is damaged you can prevent a spreading infection with Polysporin or a "triple antibiotic" ointment. There may not be enough plant cover so he is stressed by being visible all the time. I would not put a melleri in anything smaller than a 6'x6'x6' enclosure, and I would just fill it with large plants. He's probably dehydrated too, and you are seeing the patchy shed. Dehydrated chams don't have much appetite either. If you are coating the crix with a heavy layer of calcium it probably tastes terrible. I've had chams who would not eat crix with visible calcium dust on them. One little trick is to put the crix in a bag or box that has a layer of dust in the bottom. Don't shake them, but press gently down on the crix's back to get dust stuck to their underside. If this is a mostly grown adult cham, you don't need to dust with calcium every day. Once a week is fine as long as you are gutloading your crix well. Commercial gutloads are mostly useless. There are one or two on the market or you can make your own. There is a recipe on the ADCHAM website. One on the market that is well balanced is the gutload from Rock Solid Herpetology (they use the formulas developed by Susan Donoghue of WalkAbout Farms...they are excellent). Melleri prefer large prey, and the soft bodied insects like silkworms, tomato hornworms (cultured, not picked off a tomato plant!), roaches are good choices. Dehydrated melleri can take weeks to regain their electrolyte and fluid balance. Daily showers, lots of long, gentle hand sprayings (not a couple of minutes, but 15-20 minutes at a time), raising the air humidity of the cage with misters or ultrasonic humidifiers all help. Check out The Melleri Discovery website and I think you'll see what else you should do. Good luck!