I have 23 days to get a flat stomach…help please?

hi i had a baby a few years ago and i never really tried to get rid of my "pooch" but it’s about an inch hanging over or so if that makes sense.. i’m not really fat, i just don’t have a flat belly and i am going to a ball in 23 days and i have a form-fitting dress i would like to have a flat stomach by then. my friend and i have been doing circuit training 3 days a week and my idea was to do cardio and abs every day as well. but what do i have to and how much exercise to get a flat stomach in 23 days? please help!!
what i mean is spanx would go too high up on my back and people would be able to see it because my dress is backless
problem: my dress is basically backless….