I'm 16 Years Old And Have Recently Discovered A Large

I'm 16 years old and have recently discovered a large red bump or pimple on my vagina it's extremely painful. I saw one for the first time a few months back. But it went away after about a week. I started being sexually active 2 years ago, I stopped but started again last month and in one month have been sexually active twice. I get pimples in the area every so often but they've never been painful. How can I solve this problem without consulting my doctor or without telling my parents.