Wikipedia says people who had amnesia often can't remember having it. I don't know yet if that's true (I haven't looked into it further yet) but it makes for an interesting twist of events.
Imagine the whumpee of your choice suffering from amnesia, their loved ones try to help them remember and try not to let it be known just how much this situation hurts them. Only to have the whumpee recover and then not remember that they had amnesia in the first place.
The whumpee, in my case, would be Hiccup, of course.