Talk to Gynecologist on Hormonal Issue

my sister is 19 year old she didn’t have an intercourse but made out unprotected. her periods are irregular since a long time but this time she didn’t get them it’s been a month and she isn’t feeling any other symptoms. also she isn’t getting the vaginal discharge she feels dry down there. very dry. she got creamy textured discharge very little bit so we thought it’s yeast infection and gave her flunconazole but it didn’t work. her discharge has stopped. period is not coming. last period was in january which was also on an irregular date.