Suggest Remedy For Inflammation And Soreness In Vagina

hi im 17 years of age and sexually active, i always have protected sex and recently after sex i noticed my vagina felt a burning sensation, i washed it off but it still felt like that for 2 days and after those two days it felt for of an itching sensation for the next 3 days and on the third day it felt very itchy and uncunfertable so i checked myself and noticed the left lip of the opening of the vagina was inflamated so i went to the hospital to get checked out and the Dr. told me it might be herpies and prescribed me with anti biotix, but i dot understand how can i get herpies if i always use condomes?