A diagnosis of "98% chance you have MS" is a diagnosis of MS. Period.
None of the drugs (Copaxone, Avonex, Betaseron, Rebif) are CURE for MS, of course, but they DO promise to slow the progression of the disease. Even when you are in a remission (when there is an absence of symptoms, or a greatly reduced sense of symptoms), MS is causing problems in your brain and possibly spinal chord, and when you do get another exacerbation, it'll show as increased disability.
The steroids won't stop the progression from occurring. All they will do is perhaps shorten the length of the exacerbation. Many doctors won't prescribe them for "ordinary" MS exacerbations (and it might be what you're experiencing) because -- as your doctor noted -- the side effects of the steroids can be very serious. They'll keep the steroid use for those times when you have an exacerbation that greatly impact your ability to "perform Activities of Daily Living" -- like, you can't walk, can't bathe, can't toilet yourself, can't feed yourself, or other major activities.
What to do now? Keep track of what is happening. If it gets significantly worse..if indeed you can't do those ADL's (activities of daily living) sufficiently to care for yourself, call him back. And you might call anyway and ask about meds that can help with bladder and bowel control, meds for fatigue, and other sympton relief (which won't slow the progression of the disease, of course, but maybe will make you more comfortable).
And seriously consider getting back on one of the disease-modifying drugs (like Copaxone) and take seriously your diagnosis of MS.
...I am not a doctor, nor health professional, and don't pretend to be one, here.....