Suggest Medication For Itchiness And Swelling Of Labia Minora

My Labia minora got itchy all of a sudden then swelled up really big and it hurts slightly, i read the thing below and i dont believe i am allergic to anything because i have not changed it recently, althought this only tends to happen when i am home from school now and then but only stays swollen for a few hours ....what could it be?