What Causes Swollen Vagina?

hi my vagina is swollen on the inside i went to the doctor cause i was experencing discharge and itching they did a pelvic examine and tested me for chlymadia, trich and ghonerhea all results were negative they gave me antibiotics. the discharge and itching went away, some of the swelling went down but its still swollen on the inside. i'm really scared, what could this be?