Tania,
Since you're using a glycolic wash, I hope you're using sunscreen every time you go out in the sun, because glycolic acid is a an AHA and increases sun sensitivity which can lead to hyperpigmentation/dark patches IF you don't wear sunscreen.
And with Obagi, you need to apply an effective sunscreen as well.
Actually in general, always wear sunscreen 15-30 minutes before leaving the house.