Due to the intensity of Stevie's playing, together with the thickness of his strings, he quite often wore holes in his finger tips and caused them to bleed. These holes could be 1/4 inch deep and so he developed his own way of fixing them.
Firstly he'd fill the holes with baking powder. Then he'd put a layer of super glue over the top of the hole.
Finally, he'd press the finger onto either the palm of his hand, or a finger from the other hand until it stuck. Then he'd pull the finger away and he'd have a new layer of skin over the repair.
He would then use a nail file to file down any rough areas, so they did not catch on the strings.
René Martinez advised Stevie that if he continued doing this, eventually he wouldn't be able to play any more, due to too much damage to his finger tips.
He therefore got some custom strings from GHS in the gauges of .011 - .015 - .019 - .028 - .038 - .058 and Stevie started to use these.
(information from Texas Flood - The Inside Story of Stevie Ray Vaughan, by Alan Paul and Andy Aledort) and the following interview: https://www.youtube.com/watch?v=5SgnHUTn52M