Hi There,
Please don't freak out. I am a Physician Assistant and trained at Emory. It is very likely and common to have a swollen lymph node in the area you described. I worked in dermatology and very rarely saw cysts in that age group but it is not impossible. The enlarged lymph node most likely means her immune system is working on something coming from her ears, throat, scalp or sinus region. Such as a virus (cold). They can come and go without u noticing it. A persistent lymph node, lasting longer than 2 to 3 months does need to be evaluated. But by all means call your ped. They may want to check her ears for an infection. But be advised that the American Association of Pediatrics has said greater than 90% of ear infections are viral and should NOT be treated with Antibiotics (which only work on bacterial infections). Above all don't worry, LOL. Never mind, all rational fails me when assessing my daughter so I know how you feel, but rest assured that your daughter likely just has a swollen lymph node because she has a good immune system doing it's job. Hope this helps.