What could these bumps be? bug bites or poisonous plant maybe?

my boyfriend (M25) came home with this bump like rash on his hand last night from work. He’s a delivery driver and got it sometime during his work day. He said it’s really itchy and they were smaller last night. he just sent me a video of it while at work today and i took a screenshot of it because theyre much more raised and bigger than last night. just wondering if it could be anything urgent. he thinks it might be from poison oak or something? Thank you!!