I Am 20years Old And Iam Masturbating From 12years Till

I am 20years old and iam masturbating from 12years till now and my pennis becomes soooo lean and short it acnnot even for 1min.So help to cure this probelmSir.What are necessary steps to cure and make my strong as wellas big.If the problem will not cure i didnt marry my Girl friend sooo please help me sir Iam requesting u sir... Please reply to sir please...