I understand the initial response to worry, but the only thing that's going to give you answers is time. (I realize how much that sucks, by the way.)
If it's just rough oral, you'll feel better in a few days. If it's more, you'll feel worse, or at least not any better. Waiting a few days either way isn't going to hurt anything or cause harm.
Could it also be some anxiety? A sore perineum can be a symptom of something, but I wonder if your butt feeling warm (is it your whole butt, your anus...?) is just being hyper-aware of everything because you're so afraid of going through the prostate infection again.
I know it's not easy, but try to keep yourself occupied for the next few days, at least over the weekend, and see if you're noticing the warmth in your butt less. If things aren't improved by Monday, give your doctor a call.
In the meantime, drink lots of water, lay off the caffeine totally (unless you're going to get a caffeine headache, and then just cut way back), skip the alcohol and juices.
Let us know how you are.