Hello Peaceful210294, thank you for your question regarding having undergone 4500 hair graft transplantation seven months ago and still having a hair density issue on the top of your head. If the density bothers you, I would suggest several PRP injections. If the PRP injections do not get you the optimal hair growth density results, then I would suggest more hair transplants. For your hair transplant revision, I would suggest the follicular unit extraction technique (FUE). During FUE, single hairs are harvested and transplanted. I hope that I have answered your question regarding hair density issue on the top of your head seven months after hair transplantation. Thank you. Sincerely, Dr. J. Timothy Katzen, MD.