Physician is the skill you use to take care of your injuries. In order to do that you need bandages and water, although some wounds require different things. For example, broken bones require a bandage and a branch (to use as a splint) and frostbite just needs the presence of a fire. The bandage does not have to be at maximum condition to be used. To use physician skill, press Alt+p, and select the wound you want to heal. If the wound has been left for too long, been previously treated or has a coloured square to the right of its name, it cannot be healed.
Alternatively, the player can ask a village sage to heal them. You may ask them regardless, so that they can help whatever they can to speed the healing.
Several herbs have healing properties.
This skill can be trained in winter, by treating minor frostbites, or by walking into one of your less dangerous traps.