I would say underfed rather than dehydrated. As you say, he hasn't eaten in 2 weeks.
How are you hydrating him? I see drainage so I'm guessing it's pretty good.
I'm taking it that the cage in the background is his. It seems a bit thin on the vines and stuff, but maybe we just can't see it. What do you have in there for him?
Are you cup feeding? I'm pretty sure you can't be free ranging the feeders because they'd all escape.
What I'm about to say might sound stupid, and I don't think this is 100% of the issue, but I suspect it makes your chameleon uncomfortable....can you raise that cage up? Get it so the top of the cage is at least at your eye level, preferably a bit above? Looming seems to make them feel safer. When they are below the beings around, they view them as predators and threats.