In males it is often seen that their hairline recedes with their age. M- Shape in the hairline is quite normal as it is a sign of maturity in males. However, if the hairline receding exposes your scalp too much then that is the problem. Hairline receding is a gradual process. With time it keeps going beyond forehead and exposes the scalp part.
Medicines or other procedures like PRP or Derma roller are usually not at all helpful in this case. Follicles in the hair line are not active, hence there is very less chance of regrowth in hairline. There will be hardly any growth even in the vellus hair or baby hair as their follicles are too weak. In this case the only option for regrowth is hair transplant. However, medicines like multivitamins and over the counter products might help in slowing the process of hairline receding. Also, maintaining lifestyle and diet will help in controlling the process of hairline receding.