How Long Does It Take To Improve Swelling After Taking Antibiotics?

hi, i was bitten a week ago on the base of my leg, it seemed to be getting better then got extremley worse yesterday,(swollen,red,hot,stiff,difficulty in walking) i visited my doctor and got antibiotics, how long will it be before i see results as i was told if no inprovement id have to have an iv antibiotic what is that? im a type 2 diabetic.