When Johnny, Roy, and the sheriff are picking out fishing lures at the lake, the camera's point of view is over their shoulders looking at the lake. When the fishing boat explodes, all of them are looking directly at the lake. The camera POV changes to see them from the front, and Johnny is now looking away from the lake, as he turns in the direction of the lake and the explosion.
When Johnny and Roy help the burn victim into the camper, his back is completely burn-free and his shirt has just been cut out with scissors. Johnny said that there were 3rd degree burns all over his back.