How to get acne away?

ok. i have this huge banquet i believe is on june 1st how do i get my acne away because its a dress/tie banquet, and the dress a picked is strapless and i dont want to lokk bad(my face or shoulders) how can i get it away with out spending alot of $$$$, and fast!Oh and did i mention there is a wedding in april? oh and will it stay away? PLEASE PLEASE HELP!