Overdraw Magic (Eldritch Invocation)

You can cast a Spell with a casting time of one action as a bonus action. For every use of this ability you take 1d4+the amount of times you used this ability necrotic damage. If you are resistant or immune against necrotic damage, you still take damage as if you weren't, but it is reduced by one if you are resistant or by to if you are immune. The counter resets every long rest