The hair cycle normally consists of growing, resting and falling hairs and there is a delicate balance between these stages of hair cycle. Normally hair should regrow but if it is not happening, you should consider seeing a dermatologist.
Further information is in the following weblink
https://www.aad.org/public/diseases/hair-and-scalp-problems/hair-loss
I believe what you mean is PRP therapy.
Next Steps
Certain Dermatologists s advice procedures like PRP therapy, platelet rich plasma therapy which may accelerate the rate of hair growth. PRP needs multiple sessions roughly at 6 weeks intervals. PRP is rich in components needed for the hair to grow and become healthier. However it is a top-up treatment and has to be done in parallel to the main medications for hair fall. PRP therapy is increasingly being accepted by dermatologists all over the world.