How To Treat Irritation On Labia?

Tonight, my inner labia started to irritate me, with an uncomfortable itch. It's specifically near the top, almost touching the clitoral hood.
It has become red and swollen and I am very worried about why this may be happening. there is a bumb on the left inner labia near my clittorus. The swelling and itch are my only symptoms.I realize this could be an std, but I'm hoping to hear any other possibilities meanwhile, before I get to see a doctor.PLEASE HELP!