How to lose 23 pounds in 32 days?

im 15, 5'4" and i weigh about 143 and i want to lose 23 pounds in a month. i want to do this because im going to nationals starting on july 9. and of coarse, its at the beach. i want to be able to look good in a bikini. iv tried everything. and im starting to get a little desperate to lose this body fat fast. PLEASE HELP ME. i don't know what to eat, or how to exercise since its really hot outside, and i don't know how to get this weight off fast. i know it's not healthy, but i want to be comfortable with my weight. nothing ever works for me. i need helpful guide lines to achieve this goal! thank you for all the answeres!(: