What you circle in the 3rd & 4th images is the antenna for his earpiece.
Entry wound is from the front as seen in last image.
The reason his shirt pulls up & back on his LH side (images 3 & 4) is because the bullet exiting the back of his neck is pulling the shirt in that brief instance.
Shot was from Charlie's front at a slight downward angle.
That is this Anon's general assessment.