Did the LightGuard do what was designed to do? Then it deflected a stone or other road debris ... the LightGuard took the hit, absorbed the impact, and saved you a few hundred bucks because you're not replacing the headlight.
For very little cost you can get a replacement lens. It's very cheap insurance...
NOTE: These replacement lenses, are for current stock lens protectors that incorporate the new QuickRelease pins. If you have the older style lens, you will need to order the Quick-Release Pin/Bushing Kit. click here