I am 16 and I have an open sore to the left of my testicles. At first I think it started as a pimple that I didn't notice until it popped. I am a virgin and so I'm pretty sure it is not a STD. what is this and should I go to the doctor
If it started as a "pimple" and now it's an "open sore," your best bet would probably be going to the doctor. These days, staph infections can turn into horrible messes that started as nothing.
Please go to the doctor. All we can do is guess here. Some of the guesses might correct and come from people with fine medical education and backgrounds, but they're still no substitute for seeing a physician who can physically examine you and visit with you in person.