It shouldn't affect your shots and I wouldn't do anything to try to fix it - or worry about it. The worst possible situation would be additional lens flare from the scratches. Try shooting with the sun in the frame** for a good test of any possible problems. Then think about how often you shoot with the sun in the frame in real life. Use a hard plastic or metal lens hood for two reasons - it'll help with the flare but also give the lens a little protection.

**Looking at the sun thru a camera's viewfinder isn't exactly good for your eyes. The longer the lens, the more it's magnified so the brighter it will appear. Sometimes in doing this I'll put the camera on "A" (aperture priority, or Av) and use a moderate aperture like f8. Before I look thru the viewfinder I push the DOF button which darkens the viewfinder quite a lot. Life is much easier this way, but I don't bother with a 20mm or less focal length.