Im a guy, wish i can find a doc to help.

Im 21 male.. 5 years ago i used to do a very wrong thing. And its inserting something in my anus.. sometimes i used to make it hot by putting the solid body under hot water.. so i stopped doing this like 4 years ago.. i did this like 3 or 4 times in my entire life.. so what om feeling now is that i m feeling that my anus hole is not the normal size and it maybeca bit bigger.. note. I can control my poo well and its good. But for example when i went to the sea the last year.. the water sometimes gets inside the hole.. this is so makin me sad because im applying to the military service after 3 months.. and they do anal exam.. and ppl say that they know if someone had anal sex or not.. i didnt have any gay sex.. i just played with nycself.. so om really scared and need someone pro to explain it to me. Thanks hope u answer