As a colt she was the first in her class to get a CM.
Having been told by her mother that in her class the first fillies to get a mark were big bullies, she ran away as soon as she got it, without ever looking at it, believing everyone around to witness would think she’s a bully.

On her journey she runs into teenage Starlight Glimmer fixing up the town, seeing as she’s an older unicorn she begs her to use her magic on her mark, to remove or destroy it.
Starlight succeeds, gaining her own “CM alteration” mark, forming the idea of the town.

During the events of The Cutie Map- Part 2, when the CMs are released from the cave, her mark flutters around her before attempting to get back on her flank, but she steps on it to avoid it as long as possible, but no one returns to check on her.
Feeling betrayed, still not looking at the mark she allows it to return to her, goes back to town and paints over it.