Great story. I really like genderbender stories, but they usually involved Harry being turned into a girl and not Severus. I saw girl!Severus and just about died. *g*
I loved the name Severus chose for himself - Temperance (Ha, what a joke there!) Eileen Prinz. It's just different enough that no one would take notice but close enough to his heritage. I also like how he's not automatically beautiful, but he has good taste in clothes.
I really liked the interaction between Harry and Temperance/Severus. After all the work Temperance did to maintain her mental walls, once glimpse of Harry destroys them. The relationship between the two happened fast, and I like that Severus's first time was as a woman. I also like how you changed him back (even though I would have loved for him to stay as Temperance). The ending with the sweater and Severus being both Temperance and Severus is perfect.