@Banesephy
They uncommonly shave them off completely then redraw them with a tool literally called an eyebrow pencil. Why? Dunno, perhaps it's because they try to emulate some random stuff mature women do in terms of make-up. Women have been doing this since times immemorial, even more so in ancient Japan (look it up). By the way they grow back, in the case of your grandma she probably had thinned out eyebrows because of age or they didn't grow as she wanted and she ended up just removing them completely as opposed to having to pluck them out to give them shape.
https://www.youtube.com/playlist?list=PLutEVZey3YpPFw73XUxj75hGhD0cIK8Wk
Just in case anyone wanna know what is the Pythagora Switch mentioned in the chapter
@kaminomikan oh man, there is a secretary at a shop I have to go to time to time and she got real thick eye brow inked in. What is wrong with having eyebrows? Only think I do to keep nice eyebrows is run a 3mm trimmer blade over them once every couple months or when they look a little shaggy. They look clean and crisp for a long time
Ngl, kinda surprised that the author doesnt go for the typical "turns out she looks infinitely better without makeup" route that is used in literally every other media that has this kind of scene. Its nice that we are being real for once.