Hello, I understand you concern. Itching and swelling are usually a sign of vaginal yeast infection (Candidiasis), but you also mention an itchy purple spot and that is not typical of yeast. To make a diagnosis, I would normally need more information, such as the presence or lack of any discharge, your age and sexual activity history. The presence of the little purple spot makes me think of a genital wart. It could also be a sign of a more serious vulvar lesion. For this reason, I recommend you have that checked by a doctor in order to have a better idea of what might be the case here. In the mean time, if you notice a white cheesy discharge, I recommend you get an over the counter anti-mycotic lotion such as Metronidazole. Wishing you good health and all the best.