tears of blood

my sister got back from her surgery and her eyes were all blood shoot. and my mom said that she might have tears of blood. i knew i would get yelled at if i said what i was thinking so i just said "ummmmmm....okaaaaaaay"
what i was thinking: that would look cool, well since my sisters like 7(i think) it wouldnt look so cool, but it sounds like something from a story. but i have no current story to go with it. :(