hey i am in the same situation as you as my first choice also deferred me ^^ ah well, they didn't want us so who wants to go there, right?
wow your essay hooked me from the start because you mention the black market (i'm writing this as i read)
the "And" at the beginning of your second sentence is unnecessary.
try not to make yourself sound too dumb (which you're obviously not) when you talk about not understanding chem
why not add a little humor in your parenthetical with
(don't worry, I'm not referring to anabolic steroids)
no caps in a college essay, c'mon. and be more specific instead of saying ALL my passions, say exactly medicine and chem and bodybuilding
though the prompt doesn't ask for this, still add in how JHU will help you bc they actually want to hear your passion for the school
please take a look at mine if you have time! thanks and good luck :)