I don't recall where this story is from, but I've read it somewhere. It's a story about a guy who invents shaving microbots, which you apply in your face, who

I don't recall where this story is from, but I've read it somewhere. It's a story about a guy who invents shaving microbots, which you apply in your face, who do all the work. Iirc they were on a gel, though ultimately that doesn't matter. At some point they supposedly deactivate themselves for some reason I've forgotten, to prevent them from doing harm in case they enter the body. The end of the story is that the inventor, who kept using his microbots, eventually died of unknown cause. The autopsy showed that he had pneumoconiosis/silicosis, aka a dry, dusty lung. Because he kept inhaling them. Microdroplets of liquid, containing microbots. I believe this story isn't far fetched. Imagine you have thousands of these teeth brushing bots in your mouth. If you have some on the back of your throat, you will eventually have them in your lungs. All it takes to accumulate enough of them to cause issues is repeated use and time.