I could've sworn I had this bookmarked, but it looks like not.

It's basically what it says on the tin: mid-season-four Dean has been regressed to roughly the age of 5, but he still remembers Hell and has nightmares about it; Sam tries to comfort him.  I'm pretty sure it was before the revelation about what really happened in Hell, but child!Dean doesn't express himself quite well enough for Sam to figure it out.  I recall that one of the things Dean says is that Alastair wouldn't let him "have a name" until he said yes, and also claimed that he wanted to torture people, which Dean vehemently (if incoherently) denies.

Any takers?  I am about 75% sure that the author's LJ name began with H, if that helps...