Thanks for writing to us.
Your vaginal mucosa might have got involved due to sulfa drug reaction.
To help with your concern, take tablet cetirizine
daily and apply a mild steroid
cream like hydrocortisone cream
over affected area for few days. Do not use any harsh antiseptic lotion or soap to clean the area. Hopefully in few days the raw area should heal. If in case the response is not desirable consult a dermatologist
Hope that helps. Take care.