On the face, assuming the treatment is done correctly, it would be extremely unusual to develop scarring from Fraxel treatments.  I'm also assuming you are not prone to keloids!  You've had several treatments and you respond well.  When you go to a good laser center where they follow the guidelines and you really shouldn't have a problem.

OFF-FACE applications of the laser are another story. Areas like the neck and chest, for example, are much more likely to scar with aggressive treatments.   Also, unfortunately some doctors (really try to find someone board certified in dermatology if you can) aren't properly trained or like to treat very agressively.  This can sometime cause problems.   Hope this helps and sorry for the delay on this one!  Dr. I