I Had A CT Scan Done 3 Months Ago For

I had a CT scan done 3 months ago for a kidney stone. They said my lymph nodes were slightly abnormal and I needed to follow up with another CT in 3 months, which was done. I have now been told there is no change, and I need to see a hematologist. By the way, a week ago I ended up in the hospital with a 103 fever with back pain. Thought it was my kidney, but it was not. How concerned should I be?