Sadness_cry, I am not a doctor, but I currently carry an std known as herpes. What you described could be as simple as an ingrown hair, or it could be herpes.
I would recommend that you immediately discontinue any sexual intercourse and seek medical attention. You can call your local hospital and ask for the nearest free clinic. All cities and most small towns have clinics set up that offer free pregnancy/hiv/std testing to people that do not have insurance.
Not to scold or judge, but you should never let something like that go. If you have no health insurance and no free clinic in your area then go to the hospital and make payments on your bill. As long as you pay $5 a month they will not report you to collection.
Also, I am going to make a jump and say you would not be concerned about an std if you are not currently active. Being sexually active is a huge responsibility. You have to not only take responsibility for your own health, but that of your partner as well. That means you need to be getting tested for hiv and a full range of std’s on a regular basis.
In america there is an epidemic of std’s. I should know -- I have one. I have one because my partner, my ex husband, was unfaithful. At this point I hate him more for not being careful than I do about being unfaithful. I thank god I caught herpes and not aids, or something more serious.
Quick fact: 1 out of 4 americans is now reported to be carrying herpes. There are more that do not even know they have it. Herpes has no cure.