If you are ever worried about an animal, any animal, eating something that will damage it's intestinal tract over feed it soft bulky food. This goes for your dog that ate a chicken bone, too. Filling the gut with soft food that is also very moist will expand the gut allowing more room for whatever object you are worried about passing without damaging the intestinal tract walls. I would think that the risk of a swallowed hair is pretty remote, but that it possibly could get entangled on something indigestible and cause a blockage. If you find a hair protruding from the vent do not pull it as you could cause problems.
There is not a lot you can do if your chameleon swallows something it shouldn't other than over feed it very moist, bulky, soft food. It could take days to pass the hair. My first veiled was a fair sized male and I bought him full of very large bark substrate and rocks. He pooped big pieces of subtrate and rocks for about a week. bark chunks were bigger than a normal poop.