I use MAC Studio FIX foundation over Studio Sculpt concealer, which works well to cover the PWS on my face. Used to use DermaBlend but it feels thick and heavy, and following my laser treatments the mark was lighter so I don't need as much heavy foundation although I am sure I will always need at least some light makeup. Clinique makes a good setting powder to wear over concealer.
I am also planning soon to visit the Microskin Center in NYC which custom blends colors to match your skin. The website says it is not make up, but rather something else and it supposedly lasts for up to several days with one application, and it is waterproof. I will give an update after I visit!