I left an admittedly rude comment on an answer earlier today (requires privilege to see deleted post). I chose quite poor wording and offended the answer poster. While drafting an apology comment, the poster then deleted their answer (at 4:20 UTC). Since SE isn't like a forum and I didn't really have another way to deliver an apology, I felt bad but I had to move on.
Then I noticed I received a spree of 9 rapid-fire down-votes (between 4:27 UTC and 4:30 UTC) on a bunch of my questions and answers over the past couple weeks, including at least one answer that is objectively factual and one answer that involved a lot of research effort.
I'd prefer if these two events are unrelated and that the timing is coincidental... but I doubt it when separated by only 7 minutes. It's infeasible that all 9 of those down-votes were cast in the span of 3 minutes by 9 different users on questions and answers posted on different days. I don't know whether it was retaliatory or not, and the reputation loss isn't substantial, but I'm concerned about the cause and possible repercussions.
What do I do (or what does somebody do) about this?