It would bump the gravity and therefore ABV, but you'd be risking the body and mouthfeel of the finished product. What was your mash temp? If it was in the higher range, you might get away with it. I'd opt for the less expensive corn sugar, though.
Personally, I would strongly recommend giving it a taste before adding sugar. Let it run its course, taste it, and then add a pound of sugar if you're really unhappy.
I think you're still going to have good beer if you let nature take its course, even though it won't be the screaming monster that was planned.