It's not likely to have damaged the LED itself. More likely is that there's a bad contact at either the batteries or the switch, or that you may have gotten a crack in the printed circuit board. I'd look around the contact area for the batteries first since that might be easy to fix. Try cleaning the contacts on the LED part of the unit that touch the batteries - I've found that sometimes my similar light won't turn on when I replace the batteries and can be fixed by cleaning these contacts. Also check that the batteries are sitting at the right level - it's possible that the hard bump compressed one of the springs so that cell may not make a proper contact.