I had a bad breakout the first couple of days after my transplant. it was all over my chest too and I think the docs thought it was more from Prograf then from the Prednisone.
I have been on a steady dose of 20 mgs of prednisone since May. I was fine until about October when my face started breaking out and getting very oily. Luckily, they lowered my dose to 15 mgs so it cleared things up. Unfortunately, i just started another bump and taper (40mgs, then 30 mgs, then 20mgs) to clear up a cold I have right now. So I will probably break out a little.
Just be diligent about washing your face and getting rid of that excess oil. And it's true, once the meds are lowered and your body adjusts the side effects really aren't that extreme any more. so remember, anything that happens in teh beginning is most likely temporary.