If you go to the doc for a medical problem, I have found there are always two simple questions to ask:
1) Is my condition fatal?
2) Is it easy to cure?
If the answer to both is "no" I have found it is best to thank him, pay him, and leave. It saves untold time and money in return trips to a specialist and most things heal themselves. If they don't, he was wrong about question one and you won't be able to complain.
Bad Bob