Is this a zit or a bug bite? 😫

Tracy • Expecting baby #1! January 2020 ❄️

My husband came home from work and asked me to pop this zit on his back and he lifts his shirt up and I see this huge bump. He insists it’s a zit but I’ve never seen a zit that big in my life. However I’ve seen bug bites this big. Anybody (maybe working in the medical field) know what this could be?