Upload & Sell: On
Is that an EF 100/2.8 USM Macro? If yes, then no worries. At least, in my experience, it rattles a bit near its aft end. Should work fine.
A scratch on the front element is a different matter. That would bug the hell out of me, yet it would only matter in rare circumstances. That would be in 'contra lighting' situations, when it could increase flare. At the least, this can reduce the overall contrast in the image that you capture. At the worst, this can add an unusual 'bright' artifact or two (or more) to the image. If you do notice something 'flare-related', then step one is to fill in the scratch with black ink (fine Sharpie should do it), then try it again.