What Causes Swelling And Itching In The Labia Minora?

I have had a swelling and slightly itchy left labia minora of over 24 hours. It is really starting to hurt and now I can barely walk and it also hurts when I sit down. I have had no odd discharge or odour. What can I do to treat it without having to go out and see a doctor. Also I have never had sexual intercourse before