Sore throat and enlarged nodes for three months after (unusually) smoking cigarettes. (nothing externally visible, no fever, weight loss or sweats)?

Cancer. Smoking + sore throat for more than 2 weeks + enlarged lymph nodes = cancer until proven otherwise. You need to see your local ENT asap. The nights sweats/fever would be more likely related to lymphoma (b symptoms) but pt's with lymphoma can be b negative. Bottom line... Get this checked!
Sore throat. This requires a visit with your doctor for an examination to determine the cause of your illness which has lasted 3 months. It is doubtful that the cigarette smoking had anything to do with it, unless you were sharing cigarettes with others so that an infection could have been passed around.