Jerry Garcia lost about half of his middle finger and part of his ring finger to an axe when he was about four. It was his right hand. The injury caused no big problem since he held a pick with the thumb and index finger.

On the other hand (as it were), Django Reinhardt suffered damage to his left (fretting) hand in a fire while an adult. It forced him to change his playing style. His "single string" work eventually replaced the "cord" and "cord-and-lead-note" styles popular at the time. Most modern Rock and Country lead guitar work have been influenced by Django. Even Doc Watson and Clerence White claim(ed) him as a major influence.