Waterproof mascara is a lifesaver for sweaty, summer days and keeping lashes curled for hours. But because waterproof makeup is designed to be long-lasting and withstand pretty much anything, waterproof mascara is more difficult to remove than regular mascara. Good Housekeeping Institute Beauty Lab Senior Chemist Sabina Wizemann says that improper removal can cause lashes to fall out or irritate the skin around the eyes.