What does sneezing fix that ends the urge to sneeze?

I pretty well know that mucus building up in sensitive areas in your breathing passages triggers the need to sneeze. But what’s odd is (pardon the gross parts here) no mucus seems to fly out of the nose when you do sneeze. Whatever does come out is a fine aerosol, not enough to do much good. Also, most of us sneeze a specific number of times when we do have a need to sneeze. For some it’s once and they’re done. I’m almost always a two-sneeze guy. Some people need three or even more. But whatever your magic number, that’s generally what it takes for sneezing to do whatever it does for you. Why the regularity in what it takes to be sneezed out?

What does sneezing do to take away the need to sneeze again? Where or where does all the snot go?