The light inside was glowing green which means the batteries are charged but it still wasn't working. I shook it to listen for any sounds of something being loose inside and water came out. Like I said, it was cheap (and I wisely bought 3) so I can just swap it out with another but I shook out as much water as possible and will let it dry. That might be enough to get it back again but if not, like I said, I have 2 others at home.

I was thinking last night that I've always gone cheap on stuff and had to replace them more often than others who buy wisely. Once I have run out of these cheap three lights, whenever that happens, I'll get a decent rear light (although, maybe I should not wait so long so that if the decent one dies, let's say because the battery/ies was/were low, I'll have a backup).