It’s time for a fact on something that was so very popular for a while there – but its popularity has actually waned somewhat (mostly thanks to Twilight)…
Do werewolves retain their memory after the transformation?
Yes.
The answer, from a folkloric standpoint, is a pretty straightforward answer…
Werewolves in folklore generally remember everything.
The idea of a werewolf not remembering the things they did goes hand in hand with the modern concept of lycanthropy being an evil curse that the bearer is often unaware of in the first place and/or can be unaware of. Most werewolf in folklore were fully aware that they were a werewolf, knew when they would transform (and/or under what circumstances), or else they consciously made a decision to become one.
They retained their intelligence while transformed… (I know I harp on this SO much, I’m sorry, but it seriously bothers me, okay?)
And they also retained memory of everything they did – and, usually, they also retained full control of themselves.
Their personalities didn’t change, either.
The whole “they don’t remember what they did” thing is another byproduct of the modern conception that werewolves are “insane” and uncontrollable (post on that in detail), which is a focal point of talking about the transition of folklore werewolves into modern day pop culture werewolves.
So who popularized this concept?
It was undoubtedly popularized by the same source as what popularized so many other things we often expect from modern day werewolves, like the silver thing, which is absolutely not from folklore…
The writer for The Wolf Man(1941), Curt Siodmak, came up with pretty much all the most integral elements of modern day werewolves, or else plucked them from old folklore – or recreated/referenced them by pure happenstance, not intention. Some elements, he also got from other, older films of the time period, like Werewolf of London (1935). But we won’t get into that here – maybe I’ll discuss what did and didn’t come from The Wolf Man in a separate fact sometime!
Anyway, long story short, not retaining memories from their transformation is yet another element of lycanthropy that is very modern and was put on werewolves by recent popular culture, mostly popularized by The Wolf Man.
So if we’re talking folklore… werewolves in folklore remembered the things they did – due in no small part to the fact that they generally weren’t insane/constantly enraged and often had very different sorts of transformation triggers as most pop culture werewolves do, especially the enraged kind.