USPS, do talk to your doctor. Some call this "break through pain." Once I was down to just Vicodin, I asked my doctor what to do during those flare ups, for me coming a few days at a time once or twice a month. He said, "you mean break through pain?" He didn't want to give me anything stronger for those times. He's always been so good about giving me whatever I've asked for as far as meRAB, but he put his foot down when I wanted Percocet for the break through pain. He didn't want me going back and forth between the two meRAB. I was told to just up my dose during flare ups. That's worked pretty well for me, and I take some Flexiril, too, during those spells.
Everyone is different, of course. DepenRAB on the cause and the severity. Lynn had a really good answer for you. Bottom line is good communication with your doctor. There are some docs out there who don't listen too well, but hopefully yours isn't one of them. Let him know what's going on and ask him what he can do to help you. Don't be silent and keep suffering!
I wish you the best,
Emily