I definitely don't think you should stop yourself from going out and having a good time! Go to the beach, go to the waterpark, whatever you want. This will resolve itself and you should live your life in the meantime. I know you think it's gross but YOU'RE NOT THE FIRST OR THE LAST person to have acne! Yes, we're all self-conscious but going to have fun might also take your mind off of this. Exercize isn't a bad idea either...
But... I definitely think you need to go see a dermatologist. A physician might give you things to try, but a dermatologist sees rashes and acne all day long - They know their stuff (good ones). It might also NOT be acne, but something different, like a fungal folliculitis that is treatable (and doesn't respond to antibiotics) with something else.
Meanwhile, I wouldn't use antibiotic soaps. Use something neutral for now like cetafil or even ivory bar soap. Wash your clothes in something mild like Ivory snow, just in case.
Change out of sweaty clothes asap - This will all prevent bacteria or fungus from lingering. Take luke-warm showers too, hot water aggravates and makes you sweaty (and stimulates sweat/oil glands)
Drink lots of water - It flushes toxins from your body and helps your skin renew itself.
and get outside, go have fun! You'll be fine!
ACTUALLY, it would be wise NOT to dismiss it as something that just goes away on its own. I'm 33 years old and i've had it since puberty and w no long term improvement.
Try Dawn dish detergent, seriously. That's what clears mine up. I haven't figured out how to get it to go away completely though.