There was no exit wound in the rear, did you look at the X-rays? The Skull fracture lines show a shot entering the lower rear of the skull.
JFK did get hit from the side after the skull was fractured by the shot from the rear. The bullet that entered from the right temple area exited the top of the skull. You can see this from the autopsy photographs.
There is no proof of an exit wound to the rear of JFK.