Dark patches with uneven skin tone after derma peeling 5 years ago? What caused it? (Photo)

Hi, I am Indian male living in EU. I had derma-peeling treatment for my acne at Feb 2009 in India. Since then my skin became more dark with uneven skin tone.After 4 years last June 2013 I have been to dermatologist and he prescribed HQ and oral isotretinoin . Within 3 months use of HQ my skin became 100% normal with no black patches. Then he prescribed me a kojic acid cream and now I got my dark patches back again and feel even worse.I am afraid that the dark patches are permanent.Please guide me.