Hi i assume you had taken antibiotics for your upset tummy. Where u hospitalised. There is always upset in your bacterial flora and also repeated washing and reaction to your sanitary napkin causing this. Lowerpart of vagina urethra are nothing but extension of the same squamous epithelium of the skin. As long as blisters foul discharges are not there i would advise you to take salad fruits plenty of water and curds. You can take cap lactobacillus available. Any excoriated lining takes 2 weeks to heal.you can take craneberry juice mean while for burning urine apply castor oil or plain vaseline which will act as an emollient and prevent your local irritation. If blisters and boils are there it could be a drug reaction what we call stevens jhonson syndrome.please see your gynaec