Louis Armstrong suffered from severe calluses on his lips from excessive trumpet playing and cut them off with a razor blade!
Throughout his career, well his life, Armstrong suffered from calluses or scar tissue forming on the inside of his lips. His lips would split from time to time and make it extremely painful to play.
The lips rub up against the teeth and cause a type of callused tissue, much like what a guitarist gets on his fingertips from playing a lot. Once every five or six years, Armstrong would literally take a razor blade and cut the callus off himself. He’d then have to take three to six months off from playing to allow his lips to heal before he went back to work.
Being from New Orleans and coming from a poor background, Armstrong was accustomed to only going to a doctor for severe conditions. Otherwise, home remedies were common among his people. So, instead of going to a plastic surgeon to fix the problem properly, Armstrong took a DIY approach. He is said to have mistreated his lips more than any other trumpet player at his time.