I know it may sound stupid but I'm serious, mods please don't delete

I'm planning to do a little science experiment but before that I want to know your opinion on what exactly can go wrong.
In next week I plan to inject myself with HGH but I want to do it in the penis and see if it will become larger. What can go wrong? Any advices to make the experiment better? And should the penis be flaccid when I inject the hormone?