PETER THOMAS ROTH To use Peter Thomas Roth Lashes To Die For Eyelash Serum, begin with a clean, makeup-free eye area. Gently apply a thin, even layer along the base of your upper eyelashes using the provided applicator or as instructed. Be cautious to avoid contact with your eyes. For the best results, make it a part of your skincare routine, applying it once a day, preferably in the evening before bedtime. Allow the product to dry completely before going to sleep. Consistency is key, so maintain this routine as recommended on the product packaging. Face Serums