When I came off the pill in march this year I started to get quite bad acne (for me) after a couple of months that I couldn't control so I went to see a doctor.
I had comedons (I think they're called?) and a couple of really deep, painful zits that took ages to clear and I think a have a few scars as well, not sure yet. Mostly on my forehead, sides of my nose and chin. Not TOO bad but I was totally devastated anyway.
I was on erythromycin for about three months, started in june, ended about a week ago. It worked really fast! In the beginning I took four capsules a day and I think in just a few days I was almost completely clear. Obviously only the inflamed acne went away, I still have blackheads and a few bumps that turn red sometimes. I was supposed to use Differin gel as well but since it was the summer and I really wanted to be in the sun (I also went on vacation to a really warm and sunny place, and I burn quite easily anyway) I didn't use it.
So now that it's starting to get colder I'm going to start using the Differin gel to get rid of my last few spots.
So for me the antibiotics worked straight away!