Several years ago, I experienced "the pain" for the first time: sudden, intense, blinding pain in the head (sinus) upon descent. It's awful. On that flight, I was very fortunate to have a flight attendant who had some idea what to do. She immediately emptied a couple of small (plastic) liquor bottles, filled them with hot water and wrapped them with a tissue. I applied these to my face for nearly instant relief. There was something about the heat that helped relieve the pressure enough to make it tolerable, at least.

To this day, I haven't boarded another flight without those two little bottles. I rarely need them, but when I do... well, they are real lifesavers. I've talked with many flight attendants about this problem and haven't met many who knew about this possible remedy.

Your mileage may vary, of course, but I hope this might provide some relief to someone.