I've been wondering for weeks which was your fic, and here it is, hidden away in the first week! I read it when it was first posted, but somehow neglected to comment; it's pretty depressing, which is probably why!
In her mind, she concocted a potion that would make his hair shiny and silky, another one that would give a healthy coloring to his skin.
I find this so sad. In a way it epitomises both the entire story, and the person of Snape, with all his missed opportunities to not be embittered and alone. (OK, maybe I'm overthinking this a bit!)
The last line is beautiful - and beautifully painful, too.