So, now, it's been a week that I'm waiting for my skin to heal, but it's still not getting any better. I've used an acne cream that was prescribed by my doctor (5% benzoyl peroxide) and spread it over my face. (I know.. that was just a very stupid thing) Then after 2 days, my face literally burned! I got these huge itchy rashes all over..

Now, after a week of waiting, the red rashes turned DARK in colour! I look like I have big burn scars on my face! My doctor said to do nothing.. and that's what I'm doing.. but it's been a week.

Btw, when I touch those dark areas, they are not dry.. so I guess they are not dry skin.. which means that it will be very hard for them to get rid of.

So my question is.. is there a possibility that these marks will go away? School starts in more than a week T-T

It sounds like you managed to give yourself a chemical burn. Usually, the darkened skin will peel off and you'll have new skin underneath. (This is how some deep chemical peels work, by the way. Kind of messed up if you ask me.) Like your doctor said, don't mess with it. Just let your body heal on its own so that you don't make it worse or get scarring. It might be done healing in a week or a little bit more... or it might take longer, just depends on your body. Let it be, it's a process.

Also, you should try going down to a 2.5% benzoyl peroxide gel, as 5% is usually overkill. 2.5% should clear up most acne (even deep, cystic acne) if used properly.

Anyway, things like this happen sometimes in life. If you have to go into school with some dark patches of skin, so be it. This will not be the defining moment of your life, I promise. Just let yourself heal and don't worry about what anyone else might think.

Good luck!