You never really know if something will be permanent unless looking back on it. I've had sensory issues disappear years later, some, months later, some, just days later. Doctors told me early on that a symptom that lasts months is permanent, but my actual experience is very different.
I don't know if this is common, but for me, motor function deficits tend to be longer lasting and less transient than sensory. The longer I live with MS, the more symptoms tend to stay. Just curious how numbness affects your mobility? I had one leg completely frozen with numbness for many months but it didn't affect my mobility, I'm interested how a sensory problem can affect movement.
Since you can't really determine how long any symptom will last, I'd make accommodations after a few months just so you're not putting off living your life and instead in a "wait and see" and "hold" pattern. MS results in very much a fluid and always changing health state so it's important not to put off living your life hoping your health may improve. While you're waiting and hoping, it may just worsen, and you might have just missed out on a period where you could have been living your life with accommodations. Many people have a closet full of various mobility aids so they can still have mobility at whatever physical point they're at on any given day. Plan for the worst and expect the best.