youch. I just woke up pls lol.
Looks like a cut from glass to me. I had one like that as a teenager in my left hand from glass that got piled up in a really dumb place after a bunch of drunks smashed them all up in the skateboard bowl. I could see a little bone and lots of tendons too.
By the look of it though, nasty scar but most likel\y the very strong fibres running up through that are a are ok. By the blood I am guessing it didn't rupture a major artery either, which means you should heal pretty good.
Just make sure you get it stitched up tight right away, you don't want a wide scar band like on one I got on my shin when the filthy nurse declined to do the stitches right away. RIGHT AWAY.

