Hi, my cousin had her 5th day of period last night. but the thing is that suddenly at mid night she started to have pinching pain along with itching deep down in her vagina. it lasted about 30 or 40 minuits and than in the next morning it's gone. She is 20 years old and doesn't have sex yet. what was the reason of it?? is it serious issue ?? please let me know what to do.