Do you have access to an Obgyn? You need to be seen by a medical professional. It will ease your mind and help you get to the bottom of this. It may be a cyst. Those are common down there in some people. But they can become very painful and infected if left untreated. Also, you said you've been "a little sick". Like fever, nausea, vomiting, or diarrhea? Those could all be signs of a systemic infection. The only way to find out and feel better is to see a doctor, dear. Good luck, take care.
I haven't had any of those symptoms I've just been conjested and have a cough. There's a lump of skin that's raised above my skin where the hard knot is. I don't know if this could also be genital warts? I hope not but I don't know if warts causes a hard knot under the skin like that.