No way to unrepost a live video

I saw a live video in my feed that was just engagement bait. Some guy pretending to donate hundreds of dollars to people that comment.

I held the video to report it for spam or whatever but I accidentally reposted. Then I actually finished the report on a second try and then I realized I had no way to undo my repost.

I checked my watch history, reposts tab, everything. I just can't figure it out. I don't want that stupid scam engagement bait on my account.