Hi Islandchip,
Sorry to read of your sometimes debilitating and ongoing chronic carotidynia condition. I have recently spoken to an immunologist who suggested methotrexate to reduce the inflammation in the vessel. I have also wondered if an injection around the area with local anesthetic and steroids may be helpful like you might use for a tendon inflammation, but havent been game to try.
Who was the doctor in Paris, do you know? It would be good to have an national/international registry to see how many people are actually walking around with this diagnosis and what treatments have worked and how often.
Best of luck.