What Is The Pimple With White Stuff Near Vagina After Oral Sex?

Hi, I have had one STD a little over a year ago which was treated. I havent had sex in close to 2 years now. For the last two days my new boyfriend has preformed oral sex on me and rubbed his penis against my vagina with out a condom. And we did the same thing today and 6 hours later a pimple with white stuff at the tip of it appeared on my inner thigh near my vagina. What does this mean? Please help.