How long is too long to wait between first and second Fraxel Laser treatment?

It's not too late for another Fraxel treatment. I always combine lasers with microneedling/prp, subcision, fillers and Cosmelan to get the best outcomes for facial scarring. I recommend getting a formal evaluation with a cosmetic dermatologist. Best, Dr. Emer

You are fine. While you do not want to get repeat treatments too close to each other, waiting a little to long will not ruin anything. Depending on your facial scar, there may be better treatment modalities to use than Fraxel, but it is a good place to start. Warm regards.

It is not too late for your second round of Fraxel treatment. I generally have patients wait 4-6 weeks between sessions, depending on treatment intensity and skin tone, to allow the treatment area to heal. Four months is more that enough time between sessions for recovery.