You will find many places where castor oil is used topically to reduce the swelling of lymph nodes. Here's but one place that suggests it.
http://www.juniperandsage.com/oils/castor-oil.php
I would also use castor oil packs on your abdomen because that flushes the entire lymph system. You can learn more about all this at the CZ castor oil forum.
Here's a site that explains how to make a castor oil pack. I find that cotton flannel is just as good as wool.
http://www.edgarcayce.org/health/database/health_resources/castor_Oil_Packs.asp