one of my first gigs I was practicing in the band room beforehand and the tips of my fingers started to get sore so I stopped playing until I got on stage. During this time they decided to swell up a bit on me- fine I thought, I can get through that. I play with my fingers but chucked a pick in my back pocket just in case (I am NOT a pick player, can't use one to save my life). Anyhoo, about a third of the way into the set realised my finger tips had blistered up something rotten- so I thought I'd play through the pain. Two thirds of the way through the setlist they burst, all over my strings. horrible mess. I try to get the plectrum outta my back pocket, succeed (takes me about 10secs), start playing but the pus means that it falls out of my fingers and onto the floor within 2 bars. Safe to say by the end of the gig my popped blisters had blisters starting inside them.
Thank god for callouses.
*edit* oh, and new strings