If you are telling the truth and this is the only time he's ever hit you, then I can see trying to get the charges dropped.
If he has no recollection that he "popped" you in the lip, then your drinking is probably not a new item, and I worry that the hitting is not either. People don't usually drink that heavily till they don't remember things unless they do it regularly. So my worry is that he's regularly a heavy drinker, and you may have left out details, like other time's he's hit you.
If he's regularly a heavy drinker, then living together is a bad plan. Heavy drinkers rarely treat their women like queens. And if you were drinking heavily, then the lovey dovey wasn't going to work anyway, as lots of alcohol ruins the sex. That's just a fact of life.