While it is not a terrbly hard fix for a repair tech, most players do not have the ability to perform this type of repair. First, the lacquer finish is most likely a baked on form of lacquer or epoxy. The tech isolates the area, buffs down the lacquer around the sight, re-lacquers (hopefully matching the tint) and voila! the scratch is gone.
See a tech, or live with the scratch. Remember, you are not playing the finish on the horn, but the horn.