Do you peoples know the disease called Haemolacria? It is a very rare condition that make you cry tears that are partially composed of blood. It also make you sweat blood, even if it’s less spectacular.
I know that because I had a very severe form of it when I was alive. The strange thing is that I didn’t need to be sad for that to happen: it randomly triggered several times during the day. It can be very scary and annoying. There is no way to know when it is gonna start. Imagine you are doing an essay and suddenly, blood start dripping on your copy. Or you are trying to eat a soup and blood start spoiling it. Needless to say, having social interaction can become very difficult.
A doctor in the Underground told me it was a simptom of hormonal change and that it should be less severe after my puberty, but I died before. The only good thing was that I scared a lot of humans on the surface with that.
Now you know were my red eyes came from.