Yes, as Tracey said, a relapse lasts as long as it damn well pleases.
Often, a relapse can last so long you barely notice when it’s improving. Until one day you realise that your leg / arm / eyes / brain / etc is feeling better.
Re steroids, they also have a mind of their own. I’ve tended to take them if I catch a relapse nice and early. If you’ve had the symptoms of the relapse for weeks or months, chances are the steroids won’t work. But catch it in the first few days and they can be little miracle workers.
The aim of steroids is to speed up recovery time, by reducing the inflammatory action which your immune system is producing. They aren’t a ‘cure’, and they don’t always work. Having them too often is a bad thing too.
And they have some nasty side effects, from the vile taste in your mouth, to not sleeping, teeth grinding and agitation. Their after effects can be crap too, leaving you feeling like a donkey has stomped all over you.
But, when they work (and I just had a relapse and steroids that worked like angels were sorting out my immune reaction), they are brilliant.
Just don’t take them if you have an infection or a virus, even a cold, they stop your immune system from dealing with the infection, so it can go bananas.