Storm/Rotogrip OOB polished finishes are difficult to nail exactly.  Just off the top of my head, I believe Storm/Rotogrip suggests using 600 US grit sandpaper for the underlying base grit, then use Storm Step 2 abrasive polish with medium pressure for about 15-30 seconds per side to bring it up to a surface similar to how it comes out of the box.  I personally do not like the super shiny OOB finish on Storm/Roto balls (they tend to be very oil-allergic and too snappy off dry for me), so I've never actually brought a ball back up this way.  However, if you have not ever repolished the cover on your Cell Pearl, it's probably tracked up and smoothed out some from how it reacted OOB, so it should be easier to get that kind of finish.

Unless the scrape is fairly deep I would not worry about sanding it all off, just go through the steps to do the surface touchup.  If it's deep enough to worry about, take it to a pro shop that has a Haus or similar refinishing machine.  --  JohnP