You can protect an old wound so carefully that healing starts feeling like betrayal.

An injury that has been guarded for a long time can become part of how you understand yourself, and improvement then feels like a betrayal of what happened. Letting the pain fade seems to imply it was not that bad, or that the person who caused it is being let off. So the wound gets maintained, out of loyalty to a version of yourself who needed it taken seriously.

If getting better feels wrong, name what you are afraid the healing would mean. Usually the fear is that the harm will be forgotten or minimized. It will not be. You can hold that it was real and serious and still allow the pain to stop being current.