I too have oily sensitive skin and still occasionally break out (in my 40s). I have tried lots of products over the years and stick to only using a few b/c I react so much. I also have a few acne scars but they are more like pits rather then hyperpigmentation.
Alpha-hydroxy acids might be good to try, such as glycolic acid, and retinol /retinoid products. These will exfoliate the skin and help produce new skin. I have had good results with them. They will also make you more sensitive to the sun (as noted above). A good sunscreen that I use since it works for oily skin is MyChelle (medium to pricey, but I only use a little):
http://www.iherb.com/MyChelle-.....11076?at=0
I also have this product and have used it on scars in general but only so often on my face:
http://www.iherb.com/Derma-E-S...../6375?at=0
I know people who like it for use with hyperpigmentation scars, and they seem to have had improvement. The reviews on the seller's site are mixed though. It's made with onion skins and a certain ingredient in them helps reduce scarring for some reason.
(If you want to try these products, you can use the code "RUG268" to get a small discount at iherb. You can also check out natural product retailers in your area.)
Above, Accutane was recommended, but DO speak with your doctor. Some people have good results on it. I can't say that I have. It did clear up my skin a little each time I was on it, but problems returned when I went off. I didn't have really bad acne to begin with, so the super-strength med wasn't really necessary. It did very little to improve my scars though. I also had health problems as a result, including very bad depression. Try something else first, and use this only as a last resort.