Over Channeler Feat/Optional Rule

I'm looking to see what people generally think of this feat/optional rule in terms of clarity, theming, and balance.

Over Channeler
You are adept at pushing yourself in exchange for magic but at a price.
Once pershort reset you may use a Bonus action to recover an expended spell slot up to 5th level by spending the number of Hit Dice equal to the spell slot. When Hit dice are expended in this manner roll them and you take that much damage, this damage cannot be reduced in any way.

The general theme of this feat/optional rule is based on the many stories of a hero pushing themselves for that burst of power they need to overcome some challenge but that power always comes at a cost.

  • Yennefer from the Witcher Show at the Battle of Sodden Hill
  • When A Channeler in the Wheel of Time burns themselves out
  • Luke Skywalker vs Kylo Ren
  • This list could go on forever

On balance, I recognize this does give more power to casters but I generally would think the price of taking damage and subsequently giving up the chance to heal using those hit dice during a short rest would balance out the extra bang.

Optional Further Limitations
I opted not to include these as part of the feat but with the possibility of this being viewed as unbalanced or too easily exploitable
1. Change it so you can exchange hit dice for Sourcery points instead of spell slots
2. Limit this to only Sourcers and Wizards.
3. Reduce your maximum hitpoints by the amount of damage you have taken