Whats the Proper Way to Use Tazorac Gel and Obagi Blender Together to Treat my PIH?

Dark pigmentation on the skin can be caused by genetics, hormones,
and sun exposure. I would use a carefully curated protocol of laser
therapy, fractional ablation, Covalent peels, and topical creams. The
most important step is first starting Melarase creams for at least 6 to 8
weeks. 
AM: Melaclenz, Melapads, Melarase AMPM: Melaclenz, Melapads, Melarase PMBest, 
Dr. Karamanoukian
Realself100 Surgeon

Best treatment for PIH in my opinion, is neither Tazorac, a retinoid, nor Obagi Blender, also a retinoid.  Use a mild corticosteroid against inflammation, cosmetics to camouflage, sun protection/avoidance (no tanning), and patiently await the lapse of a six to eight month interval for resolution.