Need help---yeast infection???

Sorry if this is TMI, but I have never had a yeast infection or UTI. The last 2 days I have been really itchy down there, just on the outer part of the lips, nothing inside. I have used the vagisil wipes, which help with the itching temporarily. This morning my lips are swollen and red, I suspect from itchiness last night. I have no odor or abnormal discharge, nothing I can see externally. Could this be a yeast infection? How do I treat it? And if I don't have a yeast infection and do treat it, can it through off my normal flora and create a yeast or ut infection?