Teddy wasn't expecting Remus to realize who he was. He knew that this version of Remus didn't have a son. He also knew that any version of Remus that might be here wouldn't realize that Teddy was his son as Remus had died when Teddy was a mere baby. So any version of Remus wouldn't recognize Teddy as his son. And Teddy was okay with his, he had accepted the fact that Remus may not recognize his own son. But he found that he wanted to spend time with Remus, he wanted to get to know the man. He wanted to know his father. Even if the man didn't realize he was a father yet.
"My name is Teddy," he offered, his voice quiet. He was in a library, after all. "My given name is Ted Remus Lupin, but everyone calls me Teddy." He wasn't sure how this information would go over, but it was worth a shot. It was better than making Remus believe that he didn't have anyone related to him in Storybrooke.
"I believe you to be my father. Though... this version of you doesn't have a son. Storybrooke is strange like that." Teddy knew that he wasn't very good at this sort of thing, and hoped that he wasn't making a complete mess out of the whole situation. "You had a son in April of 1998 with a woman named Nymphadora Tonks. I am that son. I am a metamorphmagus like my mother, but I am not a werewolf." The word werewolf was rather soft, he figured that Remus wouldn't want everyone and their mother to know what he was.