What Causes Itchy White Lump In The Labia Majora?

Hello, I am itchy under my clitoral hood, slight white buildup and my labia are swollen and itchy as well. I do not have a discharge from my vagina so I don't think it is a yeast infection. I am 38 years old, 178lbs, I haven't been sexually active until just recently. The itching started after having oral sex for the first time in 3 years. I was pretty sore after that experience.