Take a picture of it? I made a collage and have a 3x5 index card on it that had information about something I loved. But that was 20 years ago and the card (it's an orange-colored index card) is completely "blank" now, has totally faded and looks odd as part of the collage now. It makes me a little sad but I can remember what it was about, why I put it there, and it's kind of neat having that "secret" that is just mine.

Take a picture of your scar before it fades and put the picture in a "special" place with other keepsakes. Then in 20 years you can show it to your daughter, especially if she has trouble with cutting :-) It's good to grow up, I promise! Is painful/sad sometimes but good.