How can I get out mascara from my favorite shirt?
And no that is not my mascara!
I've heard of "lipstick on your collar" but not mascara on your shirt! lol
Have you tried using a pre-treater like "Shout"?
Another tip would be to use a cloth to dab eye-makeup remover on the shirt to remove the stain, then wash as normal.
Remember not to put the shirt in the dryer until you are certain the stain is gone.