Blood Armor

A barrier of bloody tendrils leaps from your body to protect you from greater harm. You immediately lose 1d10 hit points and then you can spend and roll any amount of your remaining hit dice. Until the start of your next turn, you gain temporary hit points equal to the amount rolled plus your Constitution modifier.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, you can roll one additional hit dice for each slot level above 1st.