Rewritten ...

“... thing is, Amy, everyone’s memory is a mess.
Life is a mess. Everyone’s got memories of a
holiday they couldn’t have been on, or a party
they never went to, or met someone for the first
time and felt like they’ve known them all their lives.
Time is being rewritten all around us, every day..."

                                                                                                                     - The Doctor

                                                                                                                        (Mini-episode: “Good Night”)

So it got me thinking:

At Trenzalore, the Great Intelligence jumps into the Doctor's time-stream and starts changing things.
Then Clara jumps into the time-stream, and attempts to rectify things.
Then the Doctor jumps in, and apparently the time-stream starts collapsing in on itself.

And after all this, Clara sees a face she hasn't seen before - in any of her myriad incarnations:
The One who broke the Promise. The One who did what he did in the name of Peace and Sanity.

Well, what if, the reason she hadn't seen him before was simply because he had never existed
- until that final moment?

“TIME IS BEING REWRITTEN ALL AROUND US, EVERY DAY.”