How Can I Repair Hypopigmentation from an Old Obagi Blue Peel?

Hypopigmentation may not improve with hydroquinone.  Beware of rebound hyperpigmentation, so you may want to switch over to a milder skin lightener such as Melarase. Raffy Karamanoukian, Los Angeles

Hypopoigmentation after a cosmetic procedure is unfortunate and difficult to treat. Sunscreen will prevent damage to surrounding skin which can accentuate the different pigmentary states of the skin. 

You may need to be very careful if you have the type of skin that hypopigments/scars easily. Fine lines can usually be treated safely with fillers. Milia can be treated with extraction or electrocautery. Unfortunately, it will be very difficult to stimulate repigmentation in an area that has been hypopigmented for so long.