Flea from RHCP did an interview back in the day. (Mother's Milk Tour) He said that he got deep "holes" from the blisters on his main bass thumb he would use. He would take crazy glue and put down in there and it would harden up making his thumb last a little longer for shows. Dunno what the repercussions of putting crazy glue in an open sore is but...hey...it might work.
