What do I do if a doctor insults me?

Depends. If you truly believe the doctor insulted you and got no apology from the doctor, you can contact patient relations if it occurred in a hospital or large hmo situation. You also have the option of filing a formal complaint to the state medical board (# should be in phone book or on web). Any action taken will depend on the circumstances of the interaction. Or find a new doctor.
Insult. Agree with my colleague, but recommend as first step to confront that doctor with what happened & how it felt.