These same highly sensitive areas are also parts we use all the time.Cuts on fingers,lips and the tongue tend to reopen throughout day dooming us to relive the pain again and again.Finally,the depth of the wound is perfect for exposing and exciting the nerve fibers of the skin without damaging them the way a deeper,more destructive injury can severely damage the nerve fibers impairing their ability to communicate pain.With a paper cut,the nerve fibers are lit,and they are fully operational.