Suggest Remedies For My Underdeveloped Penis

Hi, I have a question concerning my penis and puberty. I'm 15 years old and my penis hasn't grown at all. I have only grown some hair in the pubic region and under the armpits. Also when my penis in not erect, it is really small ( 0.5 inches i guess .... ) , but when it gets erect it is probably 2-3 inches.
I have no idea what to do and it's impossible for me to go to the doctor.