Demi Lovato returned to Instagram for the first time since checking into rehab three months ago after an apparent drug overdose. The superstar shared a photo of herself casting a ballot on US Election Day. She wrote, "I am so grateful to be home in time to vote! One vote can make a difference, so make sure your voice is heard!" she wrote. "Now go out and #VOTE!!!!" Last month, Lovato's mother Dianna De La Garza revealed the singer was 90 days sober.