Hi. Yesterday I Kind Of Rolled My Foot Off A

Hi. Yesterday I kind of rolled my foot off a curb, and it hurt very badly. There is no bruising and it doesn't look very swollen, but today it hurts even when I'm not on it. And when I do walk, it feels way worse. It feels like cramp going through my foot nonstop while I'm sitting. Will it get better on its own? I've never injured my foot before.