I've Developed A Small Lump Under The Skin Next To

I've developed a small lump under the skin next to my labia minora, it's in between the lip and labia. It's about the size of a pea and it's become very tender and it feels tender to walk. There is no whitehead or anything to pop. When I pull the skin back you can see that there is a lump but that's it. It's made my lip appear slightly swollen, except it doesn't really look swollen, just a little bigger than the other. I've also had white milky discharge with no odor, there is no redness or itching. I am sexually active but only with one partner that I have been with for over two years and I've never had a problem like this. He has no STDs and has not been with anybody else.