The thing about a flare up (as it is called in the trade) is that it makes the pain feel louder than a rock-concert, feeling as though you have run a marathon and that everyone is shouting at you.
Yesterday I waited to see if a friend was still able to go out in the evening, but I didn't find out until much later in the day she wasn't available. I had held-off taking any painkillers, but then felt it was safe to succumb, but I also just wanted to retreat into my shell like a tortoise. I had a bath (as that relaxes and warms me up) and then went to bed with a heat-pad. It is not always helpful to hide away, but sometimes it is necessary to feel less shell-shocked and because it is just so exhausting being in pain, carrying around a ball and chain.
When the noise subsides or reduces to a whisper, it is possible to function again, until next time.