Deathmark Shine on you Crazy Diamond

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

• Increase your Constitution score by 1, to a maximum of 20.
• Your soul shines bright causing you to give off light in a 30ft radius and dim light for 60ft more.
• Once per long rest you can choose to flare the light shining off of you causing blindness to enemies within 30ft for 1d4turns.
• After the first use you take 1d12 damage that cannot be healed by any means other than a long rest to use this ability again.