My skin became terrible when I hit 30, and has only just calmed down at 44. I was on Dianette AND a daily antibiotic for years.
Maybe it was coincidence, and the spots diminished because of my age (though I've just had a dd, so my hormones must still be swilling about), but in the course of my endless net surfing looking for enlightenment, I came across a website called acne.org (The Regimen). This recommended benzoyl peroxide at just 2.5% strength, all over the affected area twice a day. I had had bp before, but in much higher strengths, and only on individual spots. Anyway, my spots have gone pretty much after following this regime.
I am sceptical by nature, especially about internet 'wonder cures', and only tried this because bp is cheap and readily available. But unless the spots disappeared by coincidence, it worked. I now buy direct from the website, though I am charged customs duty. The website's originator is insistent that using bp at more than 2.5% is counter-productive because it strips the skin and makes it more prone to angry reactions and thus more spots(+ bleaches towels, etc).
So there it is. Maybe just coincidence but I daren't stop using this stuff. I did stop, incidentally, when I was pregnant, just in case it could be harmful, and got some zits - but maybe that was a pregnancy thing.
PS: I put on 5 stone while on Dianette. Size 8/10 until age 30 - now HUUUUUUGE!