I had an FUE with 5500 grafts almost a year ago and I have no significant growth

I doubt that this patient will regrow anymore hair. I believe the transplant was a failure considering that very little hair grew. The patient also reported that his donor area was heavily scarred. This was probably from over-harvesting his donor area, a common surgery done around the world by ignorant doctors. If the donor area was over-harvested, there will not be enough grafts for another surgery.  An FUE with 5,500 grafts requires a very skilled team of people paying attention to a lot of details.  Donor density is something that is rarely measured by doctors like the one who did this.

If a graft is left out of the body for 10-20 seconds, for example, it may die yet it can be transplanted. That would mean a dead graft was transplanted.  This could have happened thousands of time during the surgery. Not everyone can perform 5,500 grafts successfully.  But the worst part of this is that the hair that was transplanted is lost forever from the donor area. The scarring in the donor area produces a bald donor area that complicates the situation. This man came to the doctor with hair, it was shaved off at the time the 5,500 grafts were done, probably lost it as a result of shock loss and now almost one year later is balder than he was when he started (see photo).  This patient most likely will not be able to do another surgery so he should consider Scalp MicroPigmentation.  This is an excellent option which will look great, it is just not hair.

See https://scalpmicropigmentation.com/bold-shaved-look/