The only thing to really fix it, is by going through the logs and figure out what was gained, and take that back.
But that would take a huge amount of manpower to do I'm sure, even if you can use scripts to narrow it down.
You can't roll everyone back, because that will piss of everyone.
You can't not roll back, because that will piss of everyone that didn't do it.
And you can't really roll back people who did it, unless you do it now. Because otherwise they lose all legit play to.
It's quite the conundrum