No, that's not it.
In this story, Rin had miko powers, and she had been controlled by one of the fairies I mentioned before to shoot a purification arrow at Sesshoumaru. That's how he had been turned human. Also, when Kagome used the jewel shard to save Sesshoumaru, his appearance changed so that he had dog ears like Inuyasha, except his hair was black, and Kagome made a remark about how cute he looked.
Thanks for looking, though. The story you suggested looks interesting, too. Definitely on my "to read" list.