You can continue to see collagen renewal and skin elasticity improvement for up to 3 months after Fractional Resurfacing from an Erbium laser. I always recommend a series of 3 treatments in a row for the best results with 6 weeks in between treatments.
With the ablative resurfacing treatments, either erbium or CO2, the new collagen growth will start after a few weeks. Immediately after a treatment, people will look good because of the swelling. As the swelling subsides you will often see the original wrinkles. The new collagen will grow for several months, so you should look better at 6 months than you do at 1 month.