Tiny wooden thorns pierce the skin. If you ignore it, your body will recognize that it is part of you - the new skin will wrap it up gently, the capillaries will make way for it and then quietly wrap around it, and the white blood cells will no longer charge against it. Day after day, it settles in the depths that you cannot see, signing a silent contract with your flesh and blood.
When many years pass and you try to pull it out, all the muscles, bones, and flesh will be scattered everywhere.
It turns out that some things don't grow into you, but you grow into it. Separation is never a separation between two people, but a brutal dissection of the years of symbiosis. The skin will grow back and the pain will subside, but under that insignificant wound, there will always be a small area of flesh and blood prepared for a certain thorn that can never be restored.
When something enters life, it is destined to take a part of you with it before it can leave.