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I think your temps are a little too high and would try to lower them about 5 degrees. Possibly why he's on the lower branches. How's his drinking ? his skin looks a little chalky looking.
In the first picture of him he looks like he's about to shed, maybe just grumpy ? The Academy has a medical section that has a page on temporal gland infection. Did you just walk into his view when he opened his mouth ?
Here are a few podcasts from the Chameleon Academy that you should find useful ...
Check out "Ep 2: Surprise! Chameleon Babies!! Yay!...Yikes!!" via web:
Check out "Ep 67: Housing Baby Chameleons" via web:
Check out "Chameleons in Baby Cages" via web: