Alexander's Acidic Aura

You imbue yourself with an acidic aura that surrounds your body. You gain 1d4 temporary hit points at the start of each of your turns.  If a creature hits you with a melee attack roll while you have the temporary hit points given by the spell, the creature takes 1d4 acid damage. 

Using a Higher-Level Spell Slot. The damage and Temporary Hit Points both increase by 1d4 for every two slot levels above 1st.

"I find most creatures spit you out once you start burning in their throat." -Alexander