
Sorry, it looks like your hand will get progressively numb until it falls off
OK, Just kidding.
What you likely damaged is the Ulnar nerve. It runs over the wrist just below the thumb. If you feel in there, just above the wrist and before the hand there is a small depression in the bone structure. With zip ties or hand cuffs, especially if applied behind the back with palms facing out and away from each other, it is not that uncommon to see this nerve pinched.
From what you describe, it should clear up in a few days at most. if longer, see a doctor. To amplify what FF advised, a gentile massage of that point may help --- just don't get carried away with rubbing it or you may prolong your recovery. Movement and manipulation of your wrist as though you were making "kung fu" type circles in the air (slowly) and warm water and epsom salt soaks won't hurt either. PM me if you need more info. Let me know your progress.
when using zip ties, it is best to wrap them so they don't cut. Running one through an old sock and a cut hole in the toe is one way. Another is to use surgical tubing and run the zip through it first.

Also when used on the wrists especially, always use three: one for each wrist and a middle one that takes up the stress between them.
Other circulation problems can be created with rope or duct tape, so it is important to check your prisoner regularly for blood circulation, etc.
Hope this helps.
Tony2 --- Happy TUGS