Salivary glands are only under the lower jaw and under the ear, so this is not exactly "on the neck". Enlarged lymph nodes and eosinophilia may be a sign of lymphoma. Lymphoma is often in the small intestine, and this may be found by "capsule endoscopy". In the lymphoma, other enlarged lymph nodes within the chest or abdomen would be probably found - CT or MRI would be needed.
Causes of eosinophilia:
http://www.wrongdiagnosis.com/symptoms/eosinophilia/causes.htm
Well this suspiction about tapeworms should be cleared out first. Any parasite, including giardia and entameba, and of course intestinal worms, can cause eosinophilia. It was reported few weeks ago here on this forum, that stool test in obvious worms was false negative! Worms or their eggs frequently appear in stool, and may vbe seen with a naked eye. I'm not saying they are worms here, it's you who mentioned them.
Other frequent cause is allergy: to food (mostly to fish, shellfish, peanuts, tree-nuts), medications (any new med?), or to something what can be inhaled (new lacquer on furniture, new cleanser, mites, "fleas" in animal fur, pollens, industrial chemicals, or whatever. Nausea shortly after the meal speak for allergy, but skin or throat itching, face flushing or some rash should be also present in allergy.
Also search for "causes of eosinophilia".