I've done a very quick research and it seems that they've stopped adding them after the Forsaken Shores update(There are overall 3 scar vanity items If you don't count player creation generated ones), which is a real shame in my opinion.
It would be cool If they added a new ones that could be a reward for Megalodon or Kraken slaying commendations, maybe even the Tall Tales as a mark of experience and overall indication that the player has been through many adventures that left scars on them.
