Deathmark Killer Queen

You have manifested a deathmark. Determine its appearance. You gain the following benefits:

• Increase your Constitution score by 1, to a maximum of 20.
• You learn a cantrip of your choice from the sorcerer spell list. In addition, choose a 1st-level spell from the sorcerer spell list. You learn that spell and can cast it through your mark. Once you cast it, you must finish a short or long rest before you can cast it again through the mark. Constitution is your spellcasting ability for these spells.
• When you cast a spell or attack you can choose to cast the spell in addition to your attack once per long rest, every time after the first that you choose to cast the spell you take 2hit dice of damage that cannot be heal by any means other than a long rest.