Might be a fuse. Get a pair of plyers, manual online. Find out which one is for the horn and pull that one out and inspect it. You can tell if it's broken fairly easy. Replace it. If not that you have a more serious electrical issue.
@beastmode: Since the problem started after the collision is it possible the wiring problem is in the area close to the horn or maybe on the horn itself. If the fuse is good you might check for power at the horn connection. If you have power there the problem could be the horn itself. I should add that sometimes a broken and shorted wire will blow the fuse as well so make sure you check for a broken wire in the damaged area.
4951