Our chameleon, Leonard, has the same problem, likely due to calcium/vit B deficiency before we got him (he's a rescue, and already had the problem when he was in the rescue facility) - we have to hand-feed him by pulling his gullet/throat flap down, and popping the worms/crickets into his mouth.
Make sure you are supplementing with calcium and a multivitamin. Also make sure you are gut-loading your crickets and worms (either with commercial gut-load, or with babyfood, or with purreed veggies with calcium). Variety is key.
Your cham is young enough that this may be reversible. Our cham is fully grown, and we could very well find ourselves hand-feeding him for the rest of his life...
If your cham is dehydrated, first try enticing him with a drip system (e.g. a cup with a pin-hole on top of the cage). If this doesn't work, and you are misting him 2x daily at least, then you might have to syringe-feed some juice. You can add a little calcium powder to this - we use Kern's papaya juice (NEVER use citrus).
I think we might live right across the river from you - your profile says you are in Portland. We are in Vancouver, WA!
