The injury happened a long time ago, before the invention of speech. For this reason we don’t really know what it’s called, but for convenience sake we agree that it will be known as “the injury.”
The injury doesn’t heal. This is because what we do over and over and over to make it feel better reopens it. So is it one injury or is it a long series of injuries that runs back through our lives as far as we can see, like lights on a street at night? We’re moving in the right direction now, getting warmer all the time.