In the scar itself you likely will not get hair growth. Around you scar you likely can get hair growth as long as the follicles were not transected. If the scar was tightly closed with sutures and if they are left on for over 10 days this can strangulate the edges of skin and cause further scarring. We call those vertical little lines railroad sign. We usually close our scalp surgical scars with staples in addition to closing with a trichophytic closure such that the scar is less visible. I would wait at least 6 month to see how the scar looks. If it is not acceptable, you may have the scar revised and closed using a trichophytic closure or other methods that are available for repair of scalp scars. You can see more in our websites.
In general hairs do not grow on scars. If there is a chance that hair will grow around the scar, it may take up to one year to find out.
Scalp MicroPigmentation or hair transplant may be an option.
Wait for about 6-8 months to see if the hair will regrow. If the wound transected the hairs they will not regrow. If pressure of repair was to tense it may or may not grow, should wait and see. If no hair growth after year you may be a candidate for scalp scar repair.
You had scalp stitches and have seen hair loss and a scar. You will not know for 6-8 months if the hair will grow in this area. Wait it out.
You are most likely experiencing telogen effluvium or "shock loss." This occurs quite often around sutured areas. The tension that is created around the injured area can sometimes "shock" the hair into falling out. You are right that it can sometimes take many months for the hair to return. There is a chance though, if the area was very tight that some of the hair that fell out may not return. I have seen this and the hairs are often times those directly around the sutured area. If this is the case, then hair transplant would be a viable solution for you. If you are shaving your head I would recommend doing FUE to obtain the grafts. I still would wait 6-9 months before thinking about surgery.