Discolored mark on my lips hasn't gone away [miscellaneous]

I had a minor injury on my lip about 3 years ago and it left a darkened mark on my lower lip. I expected it to go away as it healed on its own but the mark persists till today. Does anyone have an idea for what I can do to remove this discoloration or will I simply have to live with it. I use Aco lil balm and Vaseline if that helps.