Your brain and spinal cord help control all of your actions and how your body works. They control things like walking, breathing, and speaking, by sending signals to every part of your body through nerves. Nerves also carry signals back to the brain from organs like your eyes and ears, that tell you what you are seeing and hearing. Nerves are very thick closer to your brain and spinal cord. But, as they get farther away from the brain, they continue to branch, and become very small and thin.
Because nerves near your skin are so small, it is impossible to have surgery and not cut them. Nerves often heal with your skin after the surgery. But, sometimes nerves are cut and they do not heal. This is called nerve damage. In some cases, the nerve damage can affect a large part of your body, in other cases, it only affects a small area. It might only last for a short time, or it might last the rest of your life. The symptoms it can cause are: loss of feeling in your skin; pain in muscles, bones or skin; or difficulty in controlling muscles. The symptoms often go away over time, but in some cases, additional surgery may be needed.