What it means: You just have to get on with things, even if it's painful or difficult. Where it comes from: Back in the days before anaesthetic was invented, people would have to undergo surgery without any medication or painkillers. Even when these did become available, sometimes there wasn't enough time to administer them, especially when you're stuck in the middle of a battle field. Therefore, patients were given a bullet to bit down on, including when they were having their limbs amputated to minor surgeries like having a toe removed. Surgeons used this as a distraction from the pain.
