It's not really either. Though when I had the palsy it was very sore and hurt to sleep on the side of my face. An example or two of what I get. When I chew, smile, or make certain facial movements my right eye tries to close. I can feel this happening, so because I feel it I assume people can see it. I have looked in the mirror at times to see just what my face does, and I can tell. Though again I do know to look for it. Also when I smile I can either hold my right eye open, or smile with my whole face. I cannot do both. If I attempt a full smile my right eye tries to close and I can fell the muscles quivering. Also it takes a huge effort, so I just let my face do what is easier.
I also get charlie horses in my face/neck and these are painful.
Bell's Palsy is paralysis of one half of the face due to the 7th cranial nerve being inflames for any number of reasons. My reason was never determined, though I want to blame it on a bad chiropractic adjustment or a vitamin D deficiency.