Oily Skin and Tretinoin

[scubajr]

I have been using tretinoin cream 0.025% every night before bed since March for severe hyperpigmentation (nasty brown/black scars) from acne.  At first I was experiencing the normal side effects of the cream such as dry skin and flakiness,  but for about the past month, I wake in the morning with really oily skin.  It also seems to me that the cream isn't really working anymore but that might just be me thinking that.  And on days where I forget to put the cream on before bed, the next morning my skin is even more oily!
Anyone have any ideas as to why I have such oily skin now? And is there anything I can do to make my face less oily in the morning?