If you hit your head on the floor and the damage is from that then I'd say yes. If the damage came from a 'light' skidding accross the ground after the main impact I'd go no. Check the inside of the helmet around the damage for cracks / splits.
i really cant remember if i hit my head or not. Too busy trying to get out the way of traffic lol. Will inspect it in the cold light of day bikes out of action for a while. Doh!