Well, generally speaking, you are not supposed to share eyeliner with someone else. Or it can infect your eyes, and make your eyes become pink eyes. As we know that eyeliners are made of chemicals, it can be easy invaded by some other irritants. And if you share them with some else, it can increase the risk of being infected. And then it can lead to pink eyes. As we know that pink eyes is an infection of the eye or eyes which can lead to redness, itching, irritation, and a characteristic creamy discharge in your eyes. In other words, by sharing eyeliners, they can carry many bacteria, so that it can lead to infection to your eyes, even the pink eyes, for our eyes are very sensitive to the infection. Anyway, you should not always wear eyeliners, and also should not share them with others. Besides, you can drop some eye drops in your eyes, and it can relieve your symptom. Anyway, just be careful about it.
Yes, you can possibly get pink eye from sharing eyeliner. Pink eye is an infectious disease. It is caused by bacteria, viruses and by allergies. If you share makeup or towel, handkerchief or something like that with people who have pink eye, you will have pink eye as well. What's more, if you shake hands with them and then rub your eyes or get close when they sneeze, you will have pink eye as well. Though you don't contact people with pink eye, you will have pink eye when you use old eyeliner which is tainted. If you allergic to some color of eyeliner or some brands of eyeliner, you will get allergic conjunctivitis too. So you should not share eyeliner with others and change your makeup couple of months.
Yes, of course, it is possible that other people's disease might be transmitted to you through sharing eyeliner or something personal. Because if she has got some eye disease, the bacteria would be transferred to your eyes through indirect contact, and typically you do not know where went wrong. So, you had better avoiding touching other people's personal stuff and rub your eyes without thorough washing.