FUNNY STORY! I was rushing to get into this costume because it was on the last day of the con, really late, so I wanted to apply my makeup fast. I used the paint my friend and I had mixed for the black on my coat. It's black acrylic paint and dawn dish soap. HOWEVER. It got in my eye and under my contact and basically screwed up my eye for the rest of the day no matter how much I tried washing it out. Also, since Dawn breaks down oils, it kinda burned lines onto my face until my skin healed over about a week later. So the moral of the story is, Black Acrylic Paint and Dawn Soap may look awesome, but it does not work for skin. I'm going to try something else as soon as I put on the costume again, and we'll see how that works. Hahaha.

That sounds pretty brutal D:
And now that you mention it, I can see how red your eye is. But I would have never guessed this was paint at all, the first thought that came to mind was some kind of calligraphy ink or something.