I have had a swollen lymph node behind ear and cough for 4 weeks. Not bigger. I did have eczema on scalp but now better, should I worry?

No, watch & wait. Check the node every couple of weeks. If it doubles in size, other nodes become enlarged, the node becomes warm and painful, or if you lose weight, then see a doctor. It may take a few months for the node to shrink even after the eczema has cleared. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.