The body has a tremendous ability to heal itself if we just get out of the way and let it do it's job. It should grow back, just be sure to keep it clean. Also, if you want healthy bones, nails, and hair for the future, look into taking food grade diatomaceous earth. It's done wonders for me. :)
Probably ...
btw - if you don't put your fingers in your mouth, it's difficult to bite them off ... LOL
Yes it will grow back.
There s problem of the spinal cord.Yes if treat this with ayurveda it will definitely grow.