Without even worrying about DamageType, you can simple ApplyRadialDamage with a negative value.
Healing and damaging are just different ways of saying “adding or subtracting health.”
This is exactly the functionality you’re looking for – not a hack or a workaround.
If you want to trigger additional effects, simply add a Branch node off of “Event AnyDamage” that checks if Damage is less than zero.