First, determine what is causing the hair loss. If it is because of frequently wearing a headband, hat, or pulling the hair tightly back, then it should grow back when the behavior is discontinued.
The cause of hair loss is usually hereditary. You can try taking vitamins, and using shampoos that contains ingredients to increase hair growth. There are also hair transplants.
I would consult your docter and get it looked at. don't go to a hair salon and expect them to know whats happening becuase they don't usualy learn that in collage until there 3-4 year