Nice job on holding back and not ripping into him like he deserves
Because you can does not mean you should. You dont know enough about the side effect it can/will have on your body. This is only one minor one and due to your age you can have a lot more serious side effect still to come and the more you do the worse they will get. many you will/may never associate it with the AAS use but that does not make them any less real.
Please read the above sticky notes on why you should not use AAS under 24. It's not fiction and you are not, will not be the exception to the rule even though we have all been there and though we would/might be.
Some of us got lucky, some of us deal with the side effects daily, some regret the decisions of starting early/young, some/most never come back and share their experience, most are to shy to admit they where wrong.
Some of us where smart/lucky or??? and did not start until much later even though we/I had the chance at your age and younger.