I am a 17 year old male and I have had an oily forehead since 2 years ago. Acne came with it.
At first it was just a few pimples.. then it blew up. My forehead was FILLED with red bumps/acne.
About 4 months ago, my skin completely cleared up. It stayed that way for about two months.. i am now getting red bumps/pimples on my forehead again. no cysts though.
It isn't AS bad as it used to be. only one side of my forehead has acne. but it is REALLY bad compared to a normal person.
I also have really really bad hyper pigmentation issues so my forehead is pretty much tinted red. and I am tired of it. I wouldn't really mind if I had a few pimples on my forehead. but they leave red marks all over and makes it look MUCH worse.
the thing is.. my forehead is extremely oily. After about 3 hours, it's glowing due to oil. my cheeks aren't oily at all. it's just my forehead.
is there any way to fix this problem? I moisturize every day. try not to eat too much sugar/grease. but they don't seem to be helping.
are there supplements/vitamins/cream that makes it less oily? Accutane sounds REALLY tempting but I fear the side-effects a bit... enough to make me hesitate a lot. for example, hair loss would be devastating and not worth it. also i heard it's only temporary and I don't want to be on accutane for more than a year.
what to do?
If you're going to try a supplement, Zinc is the best for oily skin!
What kind of acne are you getting on your forehead? Just lots of little whiteheads and blackheads, or larger more inflamed bumps?
I used to get quite oily skin and now I get quite the opposite (but still get acne), I found that conventional chemical facial cleansers and moisturizers were actually inducing my oily skin. Now I use a cleanser with natural and organic ingredients, ( and free of sodium lauryl suphate) and simply rose hip oil to moisturize (it's so good for scarring).
What topicals have you tried? Surely you've tried benzoyl peroxide by now?
Oh and by the way, if you only have forehead acne that isn't cystic, good luck getting a derm to prescribe Accutane. 
I have the same thing, only acne on my forehead and my forehead is very oily. I've payed tons of money to dermatologists for creams that don't work I take vitamins and they don't change anything. I'm pretty sure forehead acne is almost always due to poor diet. Check out a chinese face map, I learned alot