What Causes Swelling In The Vagina?

I wanted to know why the inside of my vagiana lips are swollen red it dosnt hurt or anything there just red and earlier when i took a bath and i washed my vagiana with soap two times then dried it than all of a sudden it started to burn and itch so i put some cold water on it and it stop burning than i scratch it than everything was fine but it's still swollwn red....what could this be? do I need to go to the doctor asap? or will it go away on it's own im very afriad of what it could be