Hello
Thanks for the query
Gardasil vaccination has no relation with the swelling. As he has gone through checkup and it is normal, no need to worry. Watch for any increase in size,any pain or
redness. In most of the cases this is
reactive lymphadenopathy and it usually subsides over a period of week to month. I would suggest you to just be watchful. FNAC may be needed for further evaluation.
I hope this answers your query effectively
With regards