I had mine done about two weeks ago. I kept my eyes shut the entire time. If I had to do it again, I'd have taken a muscle relaxant, instead of just pain pills. I had a roll of medical adhesive tape to bite down on to keep my mouth open. Even with ear plugs, the noise was very annoying, and my face hurt so much when I was done, I felt disoriented... almost drunk.
But it wasn't as bad as I thought it would be, and wasn't in any more pain than usual the next day. Breathe deep and think happy thoughts.