Erbium unfractionated ablative laser: Is the effect permanent?

I've been searching high and low and I cannot seem to find a clear answer regarding wether the effects of the erbium laser is permanent or not. Unfractionated fully ablative Erbium YAG lasers seem to only remove the epidermis, and leave the dermis unaffected. So I'm puzzled how the texture of the skin gets improved? Does the dermal cell migration get improved? or is the improvement temporary? Thanks in advance