the photo is not very clear, but it looks like the book lung was damaged during the last molt. i had a big geniculata female come to me with THREE damaged booklungs that looked very similar to those of your smithi.
she made it just fine to the next molt. the next molt came very early btw, only 6 months after the damaging molt she molted again, even though she was already 7.5 inches big. after only one molt, all three damaged booklungs were fine again.
so i wouldn't worry if your smithi is not loosing any fluid from that booklung. if she does, try to seal the wound with liquid bandage - as long as it's only one booklung, she should be fine. if the area is dry, don't do anything. just make sure she has plenty to drink and don't overfeed her. just in case this is a weak area in her adominal structure it's dangerous to feed her too well. if she is obese, that spot might rupture before or during a molt.
I would consider using coco fiber or another softer bedding instead of wood chips. This could be an injury sustained from a sharp wood chip. It looks like the flap that covers the lung got torn off. These flaps are there to minimize evaporation from the lung and to prevent dirt or parasites from entering. I have read several posts where one or more of these is damaged and the spider survives fine. I wouldn't worry but I would make sure that the water is always full and maybe even mist the enclosure lightly once in a while or provide a second water dish to provide a little humidity.