I had it last year and it was a bit strange. I first noticed it when I realised I couldn't spit my toothpaste out properly and it came out of the side. Over a few days I lost the movement in the left side of my face and went immediately to the GP as I was worried about a stroke. She just said that it would sort itself out over a couple of weeks and to go back if it didn't improve. It simply cleared up over the next few weeks.
It wasn't bad as you couldn't really notice unless I smiled because I couldn't open the left side of my mouth properly.
Apparently diabetics are more prone to this but no one really knows even what causes it or why. Just another thing to add to the list that we are more susceptible to.