What Causes Irritating Spot On Vaginal Lip?

On the very tip on my top lip of my vagina it feels raw & irritated in this tiny little spot.....no bump, no swelling, red mark, irregular discharge, or pain. jus an uncomfortable feeling-do you think its something I should b concerned about? I don't wear underware & im wondering if my pants could b the reason but this has persisted for over a month now. I don't have health insurance & I cannot afford a gyno apt right now. ive been w the same man for over 5yrs & there is no cheating on either end of our relationship