Risk of pigmentation after Erbium and Pixel Laser treatments?

I'm Asian male, skin type IV, with acne scars. My doctor said he would give me 1 Erbium laser treatment and 2 or 3 Pixel Laser treatments.He said 4 Pixel treatments wouldn't do much for my skin, so he would use Erbium first to fully target my scars properly, then use the Pixel for final treaments. He did say I might have pigmentation with the Erbium, which could be dark or white patches. The latter would be very difficult to get rid of. How likely will this happen? Will the pigmentation go away naturally?