You might check the detailing section for answers to your questions.
There are car lots who use a mobil detailer
to fix these also. Though not as good as
repaint of panel, some of their work that I
have seen is quite good. They do color match
and airbrush. Larger MBZ Dealers should be
able to supply you with a name and phone #
of who they use. They also use the Dent Wizard