HELP!!! can i lose this weight please read description?!!?!?

Ok so I'm not fat or skinny, just KINDA chubby. My chest is kinda flabby and I'd like to lose this flab is about a week, I've been lifting 15 kg dumbbells (about 500 reps a day) Is it possible to lose a bit of flab in a week if i continue doing this or do I need additional exercise?