The exact same thing happened to the pinch weld seam on the right rear side of my Mustang right in front of the right rear tire tread. The painted plastic rocker panel moulding on that side is also bent outwards together with the pinch weld seam. There are many black plastic clips that hold the painted plastic rocker panel in place which are tacked on the to the pinch weld seam underneath across the rocker panel. My rocker panel moulding does not look like it's pushed outwards. I have to take a closer look at it when it's daylight outside to see if I have the same problem as you do. The passenger side pinch weld seam is also damaged, but it is flattened upwards into the rocker panel in about a 4" to 6" inch area. But the painted plastic rocker panel moulding looks like it's undamaged. It is pushed outwards right at the location where it is clipped on to the pinch weld seam where the black clips are attached to it.
I am not sure, but I think that if my car goes into the body shop that the bodyshop technician will have to take off the plastic painted rocker panel moulding OFF the car in order to fix the badly bent pinch weld seam on the passenger side. I hope that they also put a brand new black clip on one location of the plastic rocker panel moulding. The black clip that looks like a tack is the only clip which is bent outwards. All the other black clips on the plastic rocker panel moulding seem to be intact. I don't want the technician to do a mickey mouse repair job and just bang out the bent pinch weld seam without first taking of the right side plastic rocker panel moulding. Plus he has to probably repaint the pinch weld seam after bending it back into shape. I don't want to get overspray on the rocker panel moulding while the pinch weld seam is being repainted.