Yesterday Evening My 2 Year Old Son Stepped Into An

Yesterday evening my 2 year old son stepped into an ant mound where he was biten approximately 15 times on his feet. I cleaned the bites with alcohol, applied a topical steriod, and gave him benadryl. He was fine the rest of the evening. This morning, he woke up with enlarged neck lymph nodes. Is this related to the ant bites? Do I need to seek medical attention?