Erbium lasering for whiteness after CO2 laser
No laser restores pigment cells into an area depigmented by aggressive laser resurfacing.
However, erbium fractional resurfacing can blunt the transition from the face to the neck, or if the laser was done patchwork (usually mouth and eyes), fractional laser resurfacing around this area tends to blend things in better.
It is unwise, for many reasons, to perform aggressive CO2 laser resurfacing ablatively in the face: whiteness, waxiness, atrophic skin, etc. etc....