Swollen nodes and a rash are common. These can suggest a disease that needs evaluation. I would encourage you to see your primary care physician
. He or she will likely be more helpful than the emergency room of the hospital.
Swollen nodes (or lymph nodes) are caused by a few things. The most common is inflammation. This can be caused by an infection. Therefore, it is possible that you have an infection in your groin area that is causing it. I would be concerned regarding sexually transmitted diseases if you are at risk (that is, if you are sexually active). These can often have limited other symptoms. Syphilis, gonorrhea, HIV, chlamydia should all be ruled out. Herpes can also cause this.
Swollen nodes in the groin can also occur from other body infections. A viral illness
(like the common cold or the flu) can cause this if severe. That being said, it is uncommon that these cause a rash.
Autoimmune disease can cause all of these symptoms. Disease like lupus or Wegener's can do this. These are less likely but should be considered.
Talk to your doctor
. He or she can help rule out infections and better characterize your condition. Good luck!