cut a big chunk of my thumb off please help!?

I got a pretty big chunk of my thumb cooking 2 days ago. It didn't stop bleeding for about 3 hours and continues to throb. I can't feel a lot of the skin around it and I noticed today there is a weird bubble in it. I am unsure what to do because I think I could have hit a nerve and I don't want an infection! PLEASE HELP ME! Thank you so much