5 months post op. Would PRP help increase density on my hairline? (Photo)

PRP (platelet rich plasma) injections work to stimulate growth of hair from the hair follicle itself.  It does not grow hair from the scalp in areas that do not have follicles.  The only potential benefit would be to promote growth from the follicles that were transplanted.  Since these follicles are not susceptible to hair loss and the miniturization process I don't think it would be very helpful.  It has only been five months and many of the hair follicles have yet to grow hair.  In fact, some of transplanted follicles do not begin growing their hair until at least a year.  So I would suggest waiting until 12 - 15 months when all of the follicles that were transplanted will be growing hairs.  At that time you may be very satisfied with the appearance of your new hairline.  Another option at that point would be to consider a second transplant to increase the density in the area.

Hello,
Yes prp treatment will help a lot to gain dansity and protect the existing hair. You can get it done.

Thank you for your question, This needs an in-person evaluation. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

You may be a great candidate for PRP, especially since you are following a hair restoration procedure with newly implanted follicles. Platelet Rich Plasma is great for stimulating follicular units to activate hair growth and is highly advised for anyone looking to regenerate stalled growth. Keep in mind that there is a technique with PRP extraction, it's oftentimes manual, so there can be some human error with it. Your PRP liquid should always appear cloudy or hazy, some are more yellow than others. Normally for my hair restoration cases I advise 3 treatments, exactly 4-6 weeks between each, and then one annual treatment until satisfactory growth is achieved. I highly advise consulting with an experience Hair Restoration physician to discuss a plan of action. 
Best, 

PRP treatments for the hair can help stimulate hair growth as well as hair thickness.  Typically, combine modalities lead to an enhanced result.  Please consult with a board certified specialist who can assist you with achieving the results you seek.

Since you still have many implanted follicles that have yet to mature, PRP injections will help stimulate the follicles and potentially accelorate the growth of these follicles. If you choose to have the PRP treatments done and by 12+ months post implant you still do not feel the density achieved is what you desired, you may need to consider having another round of implanting done. In our office we combine multiple therapies such as PRP injections, hair supplements, and LED helmet to aid in the regrowth process.