Black-and-white dog with blue collar

I lost my 4-year-old border collie mix, Nova, yesterday around 6pm near Watertown Square, at the corner of Main Street and Orchard Street. She's medium-sized, about 40 pounds, black with a white chest and a heart-shaped patch on her chest. She wears a blue reflective collar with a small brass bell, and there’s a tiny scar above her right eye from a past scrape. She’s super friendly but gets spooked by loud noises, so she might bolt if you call out. If you’ve seen her, please text me right away—she's part of our family and we’re really worried to have her home.