Don't worry. There is a system in place which will pick this issue up (at 3am UTC) and will reverse it. There is nothing you need to do.
The automatic serial vote script should pick this up, but if in the unlikely event it doesn't clear them all wait 24 hours and should any suspicious down-votes remain flag one of the posts for moderator attention using the "other" option and explain what happened.
The moderator team will take a look and if it is the case that the script missed any they'll talk to the community team and see if we can get them reversed manually.