Hi Webrat,
How is your chameleon now?
Did you go see a companion exotic pet SPECIALIST veterinarian before? Your chameleon's problem seems complex and it is very unlikely you will get an answer on a forum. When you have have a headache, do you go on line to ask people if you have a brain tumor or if you just have a migraine? Hopefully not, you consult a specialist and if there is a risk you have a brain tumor, you get an MRI. That's the same for animals. Your chameleon deserves it.
I am not saying your chameleon is having a severe problem but it seems like it is a chronic issue and you need to get it fixed, so you should probably find a specialist in your area (and your own vet can also refer you to a specialist, this is not offending to ask him/her that; it is a proof of trust to be able to ask). When a chameleon does not eat, many owners don't go see a vet, until they are almost dying and then they decide to go... and of course in many cases the chameleon ends up dying (not much to do at this point). And here comes the theory that if you bring your chameleon to the vet, it will die... Very logical indeed. Be more intelligent, please. Did I say that before? you should find a specialist.