Oops, I had remembered Rebuke as "until the start of your next turn".

Which makes using Hellish Rebuke the *designed* way "attack me and I punish you" strictly worse than the cheese way "I attack you, I then self-damage to hurt you". You do have to defer your self-damage to your next turn, and you get full on bonus stacking. If you do it in response to the foe hurting you, you deal less total damage.

Sucks.