Working in the veterinary field, I have seen some very serious complications caused by bee stings. Fatal anaphylactic reactions caused by bee stings are extremely common in dogs and most of them need antihistamine injections. I myself came very close to loosing my dog to one single bee sting. I am sure you don't know exactly how your chameleon will react to a sting, and a retained stinger could potentially cause a nasty abscess in your chameleons mouth, once he or she ingests it. That having been said, why risk it?
-Cala-