Ahhh someone else in the same boat as me!
here is what works for me.
take 2 showers a day, scrubbing ur back with an anti acne wash that has the little sand grit things in it- I use one by neutrigina(sp?)that works ok
Go to a deratologist and he can write you a script for BA 10%, i think it stands for Bacillic Acid- get someone to put it all over ur back (this is where a steady GF comes in handy

) and let it dry for about 10 min before you go to sleep
Start going tanning, but DONT put any of the lotion on your back, just let it get a lil burnt, it dries up the oil in the skin.
in about 2 weeks it should almost be gone.
That being said, I'm a lazy shit, and dont follow all of the above often, so you could play connect the dots on my back. But when I got someplace to be, if I follow all of the above I'm all set in a few weeks.
Just make sure you get the real powerful shit from the doc, anything that you can get over the counter just aint powerful for your back- its mostly made to be used on ppls faces, so they dont want to irritate the users face...
later
Bern