Numbness is definitely a sign of nerve damage, (temporary it sounds like), but there are several possible causes. It could be a simple matter of direct ulnar nerve pressure from the handle bar in which case you need to adjust your fitting somehow to get some of the pressure off your hands as some of the other ladies have already mentioned. It could also be related to pressure elsewhere like at the elbow or in the neck. The neck cause is also very common with long rides and worse with poor surfaces.
Did you have problems bending your wrist backward or tricep weakness?
If you did, it's likely your neck and you should see your doc for an x-ray. Really, the safe thing to do would be to see your doc anyway. If there is weakness, not just numbness, it's best to get some of the more nasty stuff ruled out.
So go get it checked OK.
Living life like there's no tomorrow.
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2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS