A cautionary tale of troubled teens, families in crisis, and the consequences when a lie goes viral, DEAR EVAN HANSEN burst onto Broadway in 2016, and rewrote the rules of engagement by adding social-media screens to 21st-century theatrical storytelling. In Pittsburgh Musical Theater’s riveting regional premiere of the Tony Award-winner, Anthony Marino Jr.’s superbly awkward Evan and the strikingly original staging are among the reasons to revisit Dear Evan Hansen if you have already seen the show. If you haven’t, or even if you have, bring tissues.