About CO2 laser, they say that it promotes new collagen but I doubt some things of the CO2 for scars

Does C02 laser remove the upper layer of the scar and that layer dosent come back? If it promotes new collagen,does it mean that the old collagen is gone and replaced by new collagen? Is more collagen a good thing for a scar? And doesnt the new collagen become old collagen again and we'll have to go through the whole process again? Please answer all the questions I'm very confused about the c02 and find answers anywhere

No doctor answers yet