Dropped stitch, what else happened?

So I know I dropped a stitch here because I saw it fall off the needle. I was knitting in the car and it was kind of bumpy lol. It was on a purl row. I already frogged back because I could not figure out how to fix it. But it doesn't seem like all I did was drop a stitch because it looks weird... can anyone tell what happened? In case it happens again I'd love to know what went wrong here. Thanks!