I don't have any formal scientific or even folkloric data for my answer, all I can do is give you the benefit of my experience.
My acne started very early, around the age of 12. By the time I was 13 or 14 it was severe, covering most of my face. It remained this way until I was 18, at which point it seemed to ease off before coming back worse than it ever had.
I must have tried virtually every known remedy in this time, both prescription and over the counter.
These are some of the lessons I learned (remember that acne varies considerably from one person to another so obviously this is not valid for everyone. Hopefully, though, someone will get something from this).
I tried most of the "clear pore" type lotions available. I found they did nothing. They did at least keep my skin clean, and I found that combining them with good facial hygene kept my pores open. But they did nothing for my spots at all.
The only type of topical treatment that worked for me was tea tree oil. It didn't do a great deal for me (and it smelled disgusting!) but it did seem to reduce the amount of big, red spots that I got. But overall topical creams did nothing for me.
I went through most of the popular antibiotics available, including minocyclin and eurythromycin. They did absolutely nothing for me at all. The only one that did have an effect was Roacutane. This is a very strong drug that How to Get Rid of Pimples is only prescribed for people with severe acne that has shown no response to any other type of treatment. It's so strong that I had to have blood tests every month to make sure it wasn't harming me. The worst side effect of Roacutane is very dry lips and skin, which is almost as debilatating as the spots themselves.
Anyway, I started on this drug at the age of 18 when my spots were as bad as they had ever been. After 6 months on the drug they had reduced but had still not gone completely. My acne lasted into my early twenties, at which point it started to diminish. By the time I was 25 the spots had virtually disappeared and now at the age of 27 I only get the occasional one. Now I use Neutrogena Clear Pore solution on my face (basically a salicylic acid solution) which keeps my skin clean and benzoyl peroxide paste when I get the occasional big one.
So what worked for me? Nothing, except time. Obviously this isn't a very helpful answer. But I'm trying to show that it is possible to do everything right (clean skin, good diet, antibiotics and lotions) and still it has no effect. If you (like me) are one of the statistical anomalies for whom nothing works then just give it time to get out of your system.
Like I say not helpful but I'm living proof that having bad teenage acne doesn't have to mean that you have it for the rest of your life.