I'm in the same boat as you--or I was until a couple months ago! I'm 20 as well and have had acne since my teens and NOTHING has worked. Dermatologists are absolutely useless for moderate to severe acne and they'll just prescribe chemicals which eventually your body creates a resistance to over time. A lot of their products are very dangerous and they either seem to fail or cause other health problems, and it's very rare that you'll ever find a cure. Dermatologists are just not very experienced with acne care; acne is hard to understand and cure, so you'll see many different methods of treating it.
I finally was so fed up that I began going to see an acne specialist. I was extremely, extremely skeptical, but she has done WONDERS (you can see her site at Raleigh Acne Treatment - Without A Dermatologist Prescription for Cary, Durham, Chapel Hill and greater Triangle area of North Carolina
). My acne is almost completely gone and the hyperpigmentation--the red spots and discoloring on the skin that people commonly mistake for scars--is even clearing up, and by the time I go back to school it'll be gone. I even forget to put on makeup some days and don't mind at all!
Acne is a genetic thing, and you can't "cure" it--if you have a tendency towards it, you'll struggle with it, but the program I'm in keeps it under control and can clear it up completely (it just requires lifetime maintenance).
Diet effects acne a LOT. So if you have moderate to severe, like me, my acne doctor recommends going off dairy for a while. Milk and cheese especially--it helps clog those pores. I have the sheets with the full dietary watch list and what causes acne, so if you want to discuss it with me further, I can send them to you!
The trick to curing acne is being VERY gentle on it. Using washcloths and pads, even soft material such as those, can be abrasive and really make it worse. I recommend only using your fingertips for it--and wash 2x a day. Dermatologists will recommend full strength (around 10%) benzoyl peroxide, but that's far too harsh on skin and will only make things worse. It's best to start out by getting a mild cleanser that's best for sensitive skin, and then following up with 2.5% benzoyl treatment. Believe it or not, moisterizer (the right kind) is very effective in clearing up acne in order to balance your skin and help the medicine to work right.
One of the "miracle" products that I use is a tiny bottle of mandelic serum, but I'm not sure if that's available online, you might have to get it through a skincare specialist.
So, if you want to start that new cleansing treatment, there's a detailed guide over at Acne.org. Besides my skincare esthetician, that's the only legit place I've found--my skincare esthetician's routines that she assigns to me are VERY similar to this regimin, she emphasizes gentle skin care and lower percentages of benzoyl, as well. Also, acne.org has a great forum :)
Please message me or email or anything if you want to talk about it more! I would love to talk to you since I know EXACTLY how you feel, haha, acne is horrible! And having just gone through treatments myself I know what it's like. Best of luck!