Why does the vulva suddenly grow a bag?

Vulva suddenly grew a package, this situation to understand is the location of the package, size, shape, there is no redness and pain associated with the symptoms? The most common should be vulvar folliculitis, vestibulitis, due to vulva and urethra anus close, often by menstrual blood, vaginal secretions, urine, feces stimulation, if you do not pay attention to skin cleanliness, it is easy to cause vulvar folliculitis, vulvitis, vestibulitis, in addition, wearing tight chemical fiber underwear, menstrual use sanitary napkins caused by local permeability, local moisture are easy to cause infection. If this package is solid, but also consider condyloma acuminatum or tumor. So vulva grew a bag, still want to go to the hospital to do an examination, even want to do a biopsy examination when necessary, see what problem is after all.