In reply to KTC:
Were you pushing yourself unusually hard? Were you wearing a top with tight cuffs (or had bunched up and was restricting blood flow?
Have a look at carpel tunnel and compartment syndrome see if either of these have symptoms that fit your case, and book a gp apointment to get a check up and be sure.
In years of climbing, whilst ive felt like my hand is going to fall off due to pump, and completely unable to move it ive never had the pins and needles as you describe except in very cold conditions.