Some reports that a Benadryl a day seems to slowly restore the smell /taste.

There is currently a study being done to see if accurate. They do have a "theory" as to why this works, but obviously at this point in time there hasn't been enough research for them to even determine that it helps ... but they are researching it.

Don't take my word for it, search out one of the news articles on this. They showed up about 3 weeks ago.