Yeah, when you are working hard, you don't notice a thing.

When I was 19 and a sub-contractor, I was building a deck on this one house. I tapped a nail, turned to the guy I was working with because I thought he said something, then turned back and there was blood all over the place. Somehow, while my head was turned away, I had cut the end of my thumb off, on a nail, not hammering.

So yeah, I can understand how drizz never noticed he got bit until later.