Does the PRP treatment works for areas that does not have any hair follicles?

It depends on your definition of no hair follicles or use of the word "bald".  If you are using the phrase "no hair follicles" to mean lack of terminal hairs, the answer is yes.  PRP can stimulate vellus hairs as stated below.  If there are no terminal or vellus hairs present, its unlikely (not impossible) that PRP will make any visible changes.  

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

PRP and the delivered growth factors are dependent upon the presence of viable follicles. It will not regenerate follicles de novo. Thus its benefits in areas with a history scarring alopecia are only seen in conjunction with grafting.
As always, discuss your concerns with a board certified plastic surgeon (ABPS), with experience in hair restoration.
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PRP  works by stimulating active follicular units to transform vellus hairs into terminal hairs. It will take hair in the telogen, resting phase, and put it into the growing phase. In general, PRP can bring back hair that has been lost in the last 3 to 5 years.Jeff Rapaport MD FAADRealself Verified All-star

Thank you for your question. PRP (Platelet Rich Plasma) treatments are an easy and natural way of improving hair thickness and also promoting new hair growth. However, these treatments will only work in areas where hair follicles are present. If the area no longer has hair follicles present, the treatments will not help. In other words, if an area is “shiny and bald”, it will not work.

Platelet rich plasma injections (Prp) require active hair follicles to stimulate growth. If the area is “shiny” and smooth that usually indicates that there are no active hair follicles. 

No, PRP needs the follicle in order to stimulate growth of hair within the follicle.  You can tell this if the skin is clear and slick in appearance.  

Hello and thank you for your question. No PRP will not work in areas where there aren’t any hair follicles. Best wishes.Dr. T

PRP works by prolonging the growth phase of hair follicles.  It can only do so if there is a hair follicle in the vicinity or nearby.  It would not work on an area without follicles.

I have never seen clinical reports that PRP has brought hair back where no hair remained and the area was bald