All that scrolling, swiping and staring down at your device is leaving its mark. With the average American glued to their smartphone for more than five hours a day , experts are warning that screen time is speeding up aging in a spot most of us neglect. Dermatologists call it “tech neck,” and it’s becoming increasingly common — even in younger patients. Here’s everything you need to know. What is tech neck? It’s the early onset of wrinkles and sagging skin on the neck caused by repeatedly