That's why a spinal problem (aside from affecting both hands and feet) sounds unlikely (not impossible). When paresthesia presents from a spinal problem, it is usually unilateral - one side or the other (or predominantly so), handedness notwithstanding. To appear bilaterally and both hands & feet suggests another cause, or as previously mentioned, multiple causes.

The MRI may shed some light on the hands, but if it's just cervical, not the feet. Another possibility for the hands is Thoracic Outlet Syndrome; there's a forum here for that too.
http://neurotalk.psychcentral.com/forum24.html

All I'm suggesting is that a more likely reason than MS is PN (albeit PN can be a symptom of MS), whatever the cause.

Another factor that causes me to question PT as the direct cause is that if inflammation/swelling or impingement had occured during that session, I would think the paresthesia would have manifested much sooner, from immediately to minutes to a couple hours - not 24 hours, but a neurologist would have more knowledge/experience about that. I DO have personal experience with that; I had a session that caused a migraine, but I had the migraine before I left the office. Other therapists have warned me about possible increases in pain/soreness, and I've had that too, but again, within a very short time, if not immediately.

You might try searching the archives here - go to the main page and use the search button along the top solid bar (that will catch ALL forums), or google: physical therapy causing paresthesia

Doc