"It's amazing what you can hear on the Subway. Even if you don't want to," so starts Fabiana Mattedi's one-woman show "Notes on Collagen" (now playing in the Under St. Mark's Theater through April 16th), in which an overheard conversation sets off a monologue that reflects on aging, beauty standards and the immigrant experience. It's a lot to cover in thirty-five minutes, but Mattedi, a New York-based actress and wri…
