Im 18,doctor said im done with puberty. penis has not grown at all(4inches). is there anything i can do?what could a urologist do to help me?

Penis size varies: Is your penis measurement flaccid, stretched flaccid, erect and, if overweight, with pressure against the fat pad over the pubic bone when measuring? A micropenis is by defintion 7 cm or 2.7 inches or less erect so you clearly are in the normal range. Often a penis that appears small when flaccid is average when erect and functions well. Try to focus on being a healthy man and worry less.