Bloodcurse

You touch a creature’s open wound and bestow a curse. As you expend a number of hit points to cast the spell, that creature must succeed on a Wisdom saving throw or become cursed. On both a success or failure, a creature doesn’t realize that you attempted to curse them, unless they have some way to detect magic. For the duration of the curse, which is a number of days equal to the amount of hit points spent, the creature can’t regain hitpoints. When the creature completes a long rest, they take 4d12 necrotic damage as the curse rots away at their body.

A remove curse spell ends this effect.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d12 for each slot level above 1st.