Is it possible to pinch a vein shut? the vein in my thumb was smashed. it is now bright blue, hard an raised. it is making my whole hand tingle.

Nah..it ain't so Joe: You caused a nice big BRUISE by whacking the thumb but it's not a vein or anything like that...it's the swelling and accumulation of fluids including blood. If it's causing tingling in the hand then, you should have it looked at right away. It may need decompression otherwise, you could have nerve damage that's permanent from the accumulated pressure that's not being released. Ice down a lot.