this seems to be an enlarged lymph node
lymph node greater than 1cm may be abnormal during infancy, so needs to be worked up.
enlargement of lymph node is generally secondary to infection in the draining area of the node or some blood disorders or due to the some chronic infection.
it would be better to talk to your doctor to check for any signs of systemic illness of which it may be a part of. you may be asked for repeat blood work.
but if there are no other symptoms or enlarged lymph nodes anywhere else on body, there should be nothing to worry, it could just be reactive hyperplasia
hope you are guided by my answer
thanks for your query
wish your daughter god health
Dr. Amit Kumar