One time when I was much younger, I had a bunk bed.
And my arm apparently slid off in the middle of night and got my blood cut off by a litle metal bar, and in the morning, I couldn't feel it at ALL.
I thrusted it as hard as I could into the wall to make sure, and not a single feeling of pain, however, a couple minutes later, I started feeling an ache there when the blood came back.