How Permanent Laser Effects Are?

Hello. Dear Doctors, tell me please, does fractional (ablative) co2 laser remove scars (from acne in my case) permanently? I'm asking because I've heard that it's impossible to fully "remove" scars with that technique, and even in the best case they will come back years later. Is it true? It's very important for me to recieve honest answer because I have to make quite important decision very soon. Thank You very much!