MS is an on-going disease that proceeds on it’s own, on it’s own direction. Many people with MS experience flare ups of their disease. Those people have remitting kinds of MS, where symptoms change and any loss of function is restored.
I have the MS called Progressive MS, which proceeds with no regaining of losses but makes a slow steady course to more disability. In my case I haven’t gotten any worse, than the paralysis in my right leg, and the back pain. So i consider myself lucky.