Hi, I Just Got Told Today By The Doctor In

hi, I just got told today by the doctor in the e.r that if I had no further symptoms that I was ok, that I didn't need to keeping drinking pills. but he bearlly gave me the shot 4 days ago, is he right? or should I get checked again to make sure? nd my second? is can I masturbate ,or will I infect my self or anyone?