What is the best way to get rid of PIH after Fraxel dual for brown skin?

I suggest seeing an expert for treatment.  This requires aggressive sun protection and lightening creams.  Best, Dr. Emer.

In my practice, I try to stay away from these combination regimens, as cortisones are non-selective inhibitors of melanocytes.  I would recommend my patients to start Melarase AM and Melarase PM for the pigmentation.
I would start with an intense skin rejuvenation protocol for age spots that includes fractional laser, Covalent chemical peels, and daily skin brightening creams to improve your skin’s complexion. Laser therapy, he adds, must be combined with a proper skin regimen to enhance and maintain youthful results.
He recommends the following skincare products for dark age spots: Melarase
MelaClenz Brightening CleanserMelarase AM: Day-time skin lightener with SPF 30Melarase PM: Night-time skin lightenerMelapads: Daily Exfoliating PadsReplenish Retinoid Cream: Exfoliating and skin-stimulating night creamBest, 
Dr. Karamanoukian
Realself100 Surgeon

Fraxel is a great laser but should not be used on patients who have type IV skin.  Please consult an expert for bleaching creams and the proper skin care treatment.  Best, Dr. Green

At our clinic we typically recommend a compounding prescription of Retin A 0.05% with hydroquinone 5% at night and an additional 5% hydroquinone in the am. If there is no response then we increase to 0.1% Retin A and 8% Hydroquinone in the evening. I would recommend you see a board certified dermatologist to prescribe you a bleaching cream for these areas of concern.  

This is treated with hydroquinone, at least 4% and Retin A. If no improvements are noted after a few weeks, go up to 6% hydroquinone.