If i stop taking medicine for a infection and it comes back even worser if i start taking it again but don't stop will it clear up ?

Likely no: We doctors do not prescribe courses of antibiotics that are longer than what is recommended. So if we prescribe something for 7 days, we mean 7 days & not "until you feel better." These number of days were determined by years of studies. So, if you restart your medicine that was stopped early, and you have gotten worse, you probably don't have enough of that medicine to clear your infection.