When I was talking with latxcvi, she mentioned something that I thought was very interesting about the scar: it's possible -- by which I mean it has not been taken out of the realm of possibility -- that Peter blew up, regenerated, and just didn't let himself heal that scar because hi, he is kind of emo and just killed a bunch of people and that was maybe some outward indicator of how he was feeling. We *do* know that Peter can shut off his powers at will, so maybe...that's what he did.

The scarring doesn't necessarily mean that the timeline changed (because he wouldn't *remember* what had happened if there were a timeline change - that's established by f!Hiro and Ando) in the middle of the ep.

So yes, Claire has been alive the entire time in 5YG and f!Hiro doesn't know that because he's not native to Timeline B. He's native to Timeline A, where Claire *died*. And since everything remains outwardly the same, he assumes that Claire still died at Homecoming. Because it's established at the beginning of the episode that f!Hiro *has already gone back in time* to deliver the message. He just doesn't know the outcome because the world he is experiencing matches what he knew from the original timeline.