I have a question about the Lore Master's damage changing feature, Spell Secrets. It says (empashis mine):
When you cast a spell with a spell slot and the spell deals acid, cold, fire, force, lightning, necrotic, radiant, or thunder damage, you can substitute that damage type with one other type from that list (you can change only one damage type per casting of a spell). You replace one energy type for another by altering the spell’s formula as you cast it.
Would this changing of the type of damage affect every instance of the damage type, or just the damage type of actual damage done? For example, vampiric touch has two instances of “necrotic damage”, but only one is doing damage:
Make a melee spell attack against a creature within your reach. On a hit, the target takes 3d6 necrotic damage, and you regain hit points equal to half the amount of necrotic damage dealt. Until the spell ends, you can make the attack again on each of your turns as an action.
Does using Spell Secrets to change the damage done by vampiric touch also change the part of the spell that doesn't do damage, but refers to how much necrotic damage you dealt? Basically, would vampiric touch still heal the caster if it dealt fire damage?