Mr. Nice Guy said:
Man hindsight is always 20/20, but you should never pull a gun unless you are gonna use it. Thats just asking for trouble.
If dude was drunk, why didn't you must whip his ass instead of pulling the gun? People get big when they are drunk, but you can't fight for shit.
I agree with what he said. Pulling a gun is only inviting trouble unless you are going to kill the person you are pulling it on.
Now, there are too many "If's" in this situation to really know anything. The biggest being, "if he remembers what happened." If he does, he might want to fight you, or call his friends and have them beat your ass, or he could break into your place, or whatever. There are all sorts of things he "could" do. It's more likely that he won't do shit until he's drunk next time, then he might remember or want to try some shit.
If he doesn't remember it...you're gonna have to go over there and beat his ass with your hands or a bat or something. Pistol whipping him is the same thing as pulling out the gun on him, only now you have assault with a deadly weapon, rather than just brandishing your weapon.
Trust me, you don't want a charge of anything with "with a deadly weapon" attached to it.