My kid used to get this after being poorly - very noticeable and stuck out. It's not unusual following illness and doctors only tend to get concerned if they don't go back down again.

My nephew had some persistent ones that required some scans but they were fine also.

Thank you for your reply it's put me at ease a bit. 

Hi Clariss,

Applebee already said as much but lymph nodes do swell in response to infection and it's not uncommon. I know someone who's glands swell this time of year due to allergies, and someone else who had one swollen lymph node after COVID. For some reason, it's more common for them to swell in some people vs others. I don't know why that is! Most of the time swollen lymph nodes go down on their own and are no real cause for concern. You mentioned it moved, which is reassuring, since lumps that are firm and do not move tend to be of greater concern

Obviously get it checked if it doesn't go down - but I imagine in a couple of weeks or so it will have gone on it's own. Hope your son is feeling better soon!