What Causes High Fever After Removal Of A Cancerous Lump?

My husband had a skin cancer lump removed about 4 weeks ago and he was fine. 3 weeks later he is running a high fever of 104,drenching night sweats (when his fever breaks) and chills. He has also had a decrease in hunger. We went to the hospital and they did blood test, Ct scans, ultrasound, urine test, then more blood test and couldn t find anything wrong except for swollen lymph nodes in his stomach and chest. The hospital said the nodes were no larger then a centimeter. They also said that my husband was 38 and was to young for it to be anything more then an infection. So after 5 days in the hospital they sent us home with antibiotics. He is continually running now a low grade fever, but a fever none the less and the antibiotics don t seem to be helping. My question is....... 1.can skin cancer lead to non-Hodgkin Lymphoma, 2. Is 38 to young to get lymphoma and 3. Is a centemeter to small to even think it s lymphoma? A concerned wife, Laura