A bit of numbness is natural since as you hang/do pull ups, you're cutting off the blood flow to your fingers so they go numb.
The fact that you can't open your hand shows that you've really tired out the muscles in your hand to the point that they can't open and close properly, which is also normal as it's just the result of a good workout. My hands were the same way after my first time rock climbing.
The fact that you can't open your hand shows that you've really tired out the muscles in your hand to the point that they can't open and close properly, which is also normal as it's just the result of a good workout. My hands were the same way after my first time rock climbing.