I have a swollen lymph node but normal blood tests?

I went to the doctors with a swollen painful lymph node under my right jaw. She checked me out and was confused because that was the ONLY swollen gland/lymph node. I also had no other symptoms. She took my blood though, and all levels were normal enough. She put me on antibiotics (Augmentin) in case it's bacterial. She also thinks it could be Cat Scratch Fever since I have a cat, but he's been scratching and biting me for almost a year, and he's never had fleas. Anyone have any ideas on what this could be?