Harry Potter 6 Question (Spoilers)
 

My neighbor and I were talking about HP6, and we both couldn't remember an answer to this:

His hand got withered destroying the ring which was one of Voldemorts horcruxes.

I believe it briefly mentioned that they simply weren't able to find a way to fix it yet.

Thanks, Josh- both of our minds' were blanking!

They could not fix it because there are just some wounds that cannot be healed. They cannot heal a werewolf bite and they simply could not hear hid hand.