[codefox1]

Agree with all that has been said. Regular sandpaper is only useful on solid wood.

I would try some artist's oils with a very fine brush to touch up the color; when you are happy let it dry for a week, and then mask and spray with tinted laquer to match examples of cabinetry of similar models available on this forum.

It would probably be easier if you ended up with a shade a little darker than the original, as it is the "grey" scale is a little less apparent than the hue. The laquer will adjust the "shine" which can be rubbed down with pumice and water after a few coats, or enhanced with paste wax.

Hope this helps