Hello Sir Iam Experiencing Regular Appearance Of Vaginal Infection With

Hello sir iam experiencing regular appearance of vaginal infection with symptoms like itching and burning, with vaginal discharge.my doctor prescribed me some medicines zimig, vizylac . How many days I have to use these medicines. And also my doctor suggested me to take smear test after one week. Is smear test is necessary???? What may be the actual cause for re appearance of the infection?....