1. Are you having sex or have had sex?
2. Are you losing weight or not able to gain weight?
3. Are you having episodes of being hot at night or sweats?
4. Have you had any blood work done recently?
5. Have you been having any diarrhea or nausea and vomiting?
6. Do you walk around outside without shoes?
There are quite a few other questions, but you have to go see a doctor ASAP as any large lymph node as you described is abnormal. Some diagnoses to think about include Herpes Simplex (like a cold sore), Syphilis, or a lymphoma. Please visit a doctor, any doctor, AS SOON AS POSSIBLE!!!