Do not bother a dealer with regards to a piece of hair. It sounds like they should be responsible for it...QA, etc...but save that sort of request for when it really matters (bad datewheel, lume dots, whatever).
2 options. Take it to any watch repair place and ask them to clean it...takes 20 minutes.
Do it yourself...but like MP said...if you don't have the proper tools and saavy, you will screw it up. To see what's involved, look at the tutorials or guides in my signature for the Sea Gull ST19 keyless works to see what's involved in removing a movement...or you can look for tutorials on swapping datewheels on an A7750 or swapping an A7750 itself pinned in one of the repair sections.