I'm looking for

That fic in which Rodney has amnesia and he calls John who is not very happy to talk to him but ends up picking him up from the hospital. Rodney doesn't remember anything, not even his knowledge about physics, he reads his own publised books and can't understand a thing. There's a part in which he goes to visit his sister and drinks lemonade because he didn't know that he was alergic.

Thanks in advance!