How bad does a scalp wound has to be in order to mean permanent hair loss in the area ? I bleeding or crusting afterwards na indication for bye bye hair ?
Any cut on the skin will produce a scar, and on the scalp no hair will grow on that scar. Even with follicular unit extraction / FUE (advertised as “scarless” surgery by some) will produce a round punctuate scar.
In general, if the injury or wound is significant there will be permanent hair loss. Even a scratch could cause bleeding, but that doesn’t necessarily mean permanent hair loss will result. Only time will tell if your hair will grow back. This time frame is around one year. If you see no hair growth after one year, then it would be safe to bet it is permanent hair loss.