staple gun + thumb = bad times

I didn't staple my thumb, but I do have a huge bruise under my thumbnail.  I was tidying up some upholstery that came lose on the sofa and managed to my thumb in between the handle and the lever.  I thought I had broken my thumb, that now I had this pulverized sack of flesh hanging from my left hand.  Anyway, I now have a horrible bruise under the nail and I can't really grip anything too well because when I try it feels like the nail is being peeled away from the flesh.