A few days ago I was hit out of nowhere with a very intense pain all on the left side of my face -- from my forehead and left temple down to my top row of teeth. My skin was also very warm to the touch just on that side, and stretching all the muscles in my face downwards to tighten the skin seemed to help a bit. The pain started to recede after maybe 4 or 5 minutes, but a dull ache and the hot skin lingered through to the next afternoon. I had been the passenger in a car for several hours that day, and it was night so all was dark except the touchscreen in the car (which had been sitting in my left peripheral for awhile), and my eyes are very sensitive to glare/high contrast, but usually it will start bothering me gradually, not instant and intense pain like this. Any other theories?