Itchy welts out of no where

So the past two nights i slept in a hotel. The first night was fine. Last night i woke up itchy but fell back alseep. When i woke up this morning i had red singular bumps on my neck, shoulder, and ribs area. I was the only one who woke up itchy? And it’s only in 3 areas. So I’m confused on what it could be?

I thought it was maybe a mosquito bite but it’s winter time? I don’t think it was bed bugs bc i didn’t see anything and the other person didn’t get any and we shared a bed?? I was wearing a tank top and flannel pj pants. He was wearing shorts only… so I’m confused as to why he didn’t get any bites (if it’s from bugs?)