If I'm hit by an undead touch attack but negative energy doesn't hurt me, am I still affected by the Con drain?

Question

I recently answered a question along the same line as this one about how energy resistance affects regeneration, but sadly I have a new variation of it.

My question is about undead, their negative energy damage, and the worst part, their Con drain from natural attacks.

I am currently playing a character who is energy swapped; negative heals them and positive hurts them. I was attacked by a wraith and its spawn. So every time one of them beat my AC and touched me (which was frequent), I wasn't injured by the touch but I took the Con drain. I'm now wondering if that ruling was correct.

Since injury poison does not affect you when DR negates the damage, and energy damage shouldn't turn off regen if it doesn't hurt you, then shouldn't you be able to ignore Con drain because you didn't take damage from the attack?

Answer 1

Officially, the effects are two separate things, though I can’t really prove there isn’t any rule that, like with poison, protects you. I’m just fairly confident that there isn’t. So you’re left to asking your GM about it. Personally, I would probably waive it in this case, but I can see the argument for not doing so (after all, actual undead aren’t protected by the drain due to being healed by negative energy, they’re protected by the fact that they’re immune to ability drain in general—and that’s a feature you don’t have).