7.5 months post op FUE there is a small empty patch that hasn't grown at all. Will this area ever start to grow? (photo)

It may take 6 to 12 months to see the results of a hair transplant surgery.  If you are concerned it is best to discuss it with your doctor.

Usually there is a reason for this. It could be traumatic graft placement in the bald patch, it could be those grafts were not kept hydrated prior to graft placement, or it could be those grafts were transected during FUE harvesting and were not inspected prior to placement. Making sure you follow up with your physician and getting answers as well as a plan to fix this is the next step.

By 7 1/2 months all the hair that's going to grow should have sprouted, though the hairs may still be thinner than they will be at a year.  If there is absolutely no growth, most likely nothing new will pop up there.  This happens from time to time.  You will need to visit your surgeon and discuss this.