I don't think that it would happen for a long time, as the chain links rome, meaning that they don't always come back to the same teeth every revolution.

You might have to turn it back over 20+ times or so.

If it's just been a couple of turns, then you could try turning the engine over backwards. Just do it slowly, by hand (no impact guns or what-not) so as not to loosen the crank bolt. Don't attempt to turn the engine over using the cam bolt.