As a general statement, retconing, "I was always here" is not something you can do without ST authorization, especially when that would require a red line to the entire scene. I again emphasize that Forum play is optional, but if you choose to play on the Forums, you accept the realities of it. Try to be considerate to your fellow players and compromise to maintain the internal consistency of a scene.
Any player, at any time, can request a scene be held for resolution until Session if you are uncomfortable with continuing in the Forum environment. I may not be able to freeze a scene that has Regional or National importance, but for local stuff, we should be able to work out amicable compromises.
Finally, while PvP is an important part of any game, please remember that this is not Vampire. Every Werewolf that dies represents a loss for Gaia and for the Sept. That is why so much of the genre is dedicated to finding less than lethal ways of resolving issues. The NPC McHenry's reaction may seem to some an exception to that rule, but I invite folks who have issue with it to investigate further if they are curious about that.