Might want to add Dr. Who spoiler to the cut title, just in case.
Not everyone will have seen it yet

Well, I'm sure they've got a retcon already prepared, afterall there's the whole River backstory still to address.

He's either going to regenerate back into himself, Rose is going to time travel back down her personal timeline or being 1 second out of synch with the rest of the universe will return him back to his original state