I found this on the site listed below.. Are they sore? My sister had Herpes and hers appears as a purple type lesoion.. instead of the blisters like most people get. Sounds like you have a STD.

Sores or lesions on the female genitalia are often caused by sexually transmitted infections (STIs). Venereal warts, syphilis, genital herpes, chancroid, molluscum contagiosum, and granuloma inguinale are STIs that cause visible and fairly classic-appearing lesions.

Precancerous changes of the vulva (vulvar dysplasia) may appear as white, red, or brown patches on the vulva, and are often accompanied by itching. The vulva can also develop skin cancers such as melanoma and squamous cell carcinoma.
http://www.nlm.nih.gov/medlineplus/ency/ar ticle/003222.htm

i have had warts but these are different and are on other areas apart from my warts soyu ohnestly think this is herpes , im worried about the purple neve r ha d nothing likr tis before the purple would it be cancerous ?

thankyou

no I don't think it is cancer.. I think it is herpes.. But I would get it checked out..