I can't stop coming back to look at this, it's just so amazing. You have managed to capture every single aspect of this beautifully. First thing I must comment on is the loose thread. The way you added the blood is so very realistic and for some reason, the most creepy part of this entire image for me.
Snape's clothes are to die for. I love the fraying fabric you added. The golden clasp is just beautiful and the colors are fantastic.
You have fully placed me in awe over their hands. They. Are. Perfect. Harry's hand is limp in a perfect way and Snape's is so calmly curled around the needle as if it were as familiar to him as a wand.
The bruising you added at the stitching wins the internet. You even made the yellow/brown at his ribs. The image is amazing and your work was well worth it. Thank you for sharing it with us!