Cellulitis treatment usually includes a prescription oral antibiotic. Within three days of starting an antibiotic, let your doctor know whether the infection is responding to treatment. You’ll need to take the antibiotic for as long as your doctor directs, usually five to 10 days but possibly as long as 14 days.
https://www.mayoclinic.org/diseases-conditions/cellulitis/diagnosis-treatment/drc-20370766

