Is a card considered "in your hand" when resolving an "After drawing a card" event?
The key scenario I have in mind: Agnes has Dr. Armitage and draws Dark Memories. She triggers Armitage's ability which occurs "After you draw a card."
If the card is considered in your hand at that point, then Armitage's ability cannot be used because one cannot elect to discard a weakness from his or her hand.
But if the card is not considered in your hand at that point, then it seems that Agnes could discard Dark Memories.
Note that this really only applies to Dark Memories at this point, as it has no Revelation effect.