If the wound wasnt open at the time of the sting then there is no need to scrape as any stingers are only able to penetrate the into the epidermis layer of the area anf would of been released when this top layer came of as far as an injection goes depending if the area is infected the might give you an injection of strong antibiotics to start the process going then a course of oral tablets if there is no infection they will just more than likly give you a topical cream to apply and let nature do the rest as i said mine took just over 3 weeks to heal.