Good for you that your pet scan came back normal. What you may be encountering is just an infection within your body at this time and you should have had a complete blood work up with differential done. This would have shown any infection if any were present. If not done then I would suggest to have your doctor do this to ascertain other possible problems. They can also do a needle biopsy of the lymph node to determine what the source of possible cause is. If I may further assist you please reply.
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