What can you do to get rid of acne in under 24 hours?

Acne: Not possible especially since we have no idea about your age, gender, extent or severity of acne (inflammed or not), what medications you've tried etc. but if you do come across such a miracle cure please share it with the rest of us.

You can't: Acne needs to be managed and the best you can hope for is changes over the course of one or more weeks. Get with your physician now; if you need it treated before the prom, a combination of topical benzoyl peroxide and an antibiotic of some sort will help but not cure you. Be prepared to take a proactive role managing this for however long you have the disease before it remits.