Vagina Pimples/Sores?

So, I was trimming down there today, and suddenly I felt a small lump that hurt a little when I touched it, it was almost like a pimple. Its slightly pink around the area and seems to have a really really small white circle or patch that looks like dead/dry skin. Does anyone know what this is? Should I be worried? In terms of sexual history, my girlfriend has gone down on me maybe 3 or 4 times, but hasn't for at least 3-4 months. What's up with my area down there?