What Causes A Red Lump Inide The Vagina?

I just found a single small red bump on the inside of my labia. The center seems to be a whitish color. It is only painful to the touch, such as wiping after urination. Any clue what it may be? Being that it's Friday night, I don't know if I can go through the weekend without the slightest clue what it may be. Please help