(quote)
" Doyle observed him backstage before a gig cutting pieces of skin off other parts of his body and Super glueing them to the ends of his fingers, just so he could play."

Ya know , this being the 21st century for crying out loud ,you'd think someone would've come up with some kind of super-strength fingertip sized "stick-on" callous substitutes.
Not only for performers , but for a much wider market : namely talented guitarits whom have gone on hiatus to focus on their dayjobs becoming careers & raise families , but have finally found time to begin working off the layer of dust on the fret neck of that Taylor or Martin only to be daunted by having to build up a new layer of callous.
I can think of several friends whose guitar prowess is hampered by the long process of building up that right amount of callous again.