my 6 year old daughter almost 7 has had a knot under her jawline for over a year now, and her pediatrician would say it s her lymph nodes that are sweeling up due to mono, so they do tests and she shows up postive for mono, but wants you have mono you will always be postive for that. Anyways, dr said lymph nodes should go away, well they haven t. Could this be a cyst or something else?