After MVD Surgery, pushing the envelope

I have been reading a lot of discussions mentioning recurring TN symptoms after an initial quiet period right after surgery. People have mentioned to allow yourself sufficient down time before getting back to light chores, work etc.
Some have noted pain returning because of trying to do more at the 2-4 week post op period, rather than allowing 6-8 week rest.
I don’t understand how the TN pain comes back because of pushing the envelope.
Don’t get me wrong, I totally understand that there is a period of time necessary to allow the brain to rebalance, and recover.
What I don’t understand is that after 2-3 weeks, if one feels well enough to take a walk, bicycle ride on level cement, work in the garden, should the body not be helped by getting some fresh air and some light activity.
I understand if the procedure is successful and the nerve is relieved through decompression, why is the terrible pre surgery TN pain resurfacing for a lot of folks.??
Is anybody able to get around after 2-3 weeks without the debilitating pain. ?? Thank you, BB