Hi, I Fell And My Chin And Cheek Hit The

Hi, i fell and my chin and cheek hit the pavement. I have like a skin abrasion and so far i've just washed it with water and put polysporin on it. One of the wounds has turned into a purplish layer which i assume is the scab but my chin just has a hard yellow layer and i'm not sure if its infected or how to properly treat it