Dent repair on metallic paint

[Calvesy]

How do I fix a dented front left wing, treat it and repaint it in metallic paint?

[depressedmgl]

Unless you have access to decent equipment and a reasonable amount of skill, any repair you make will look pretty bad, though it might be an improvement on the dent.  Any Haynes manual has a guide to doing body work repairs.  If it is a reasonably new car, you should consider taking it to a specialist body shop.