What is the Longest Between Fraxel Restore Treatment Time Before Ineffective?

Ive had a fraxel restore around 10 or so weeks ago. Im asking this because the physician wrote 6 weeks apart and when it was 6 weeks my face was still pink from laser so i went back to ask and she said i can wait till the face red/pink calm down. I ask this because i want to know what is the most time you can wait inbetween the treatment until the fraxel will become "not as effective". Its nearly 3 months now and I have not been able to take time off because I will need atleast 2 weeks recovery