Prednisone can definitely cause problems with rosacea. I've been on it since November and I can't wait until I can start reducing again. I've had mild to moderate rosacea issues for as long as I can remember and there was definitely a noticeable difference when I started taking prednisone. My doctor explained to me that it can cause a number of skin problems, like rosacea and acne, though I don't know how long it's expected to continue once you stop taking it. How long have you been off?
I don't know about whether the other meds you're on can cause skin issues, but I wouldn't be surprised if they did. I just started Humira last week and my rosacea responded within a few hours. My face flushed worse than it has in years. Luckily, I was able to cover it up with some heavy duty makeup and it only lasted a few days for a few hours at a time. I know that there are treatments for it, so I would recommend speaking to a dermatologist about it if it's interfering with your life that much. In the meantime though, I just suggest you keep some good makeup on hand for whenever it pops up. It won't make the bumps go away, but it'll help with the redness.
Good luck with everything. I hope you find a solution soon.