bites or Hives? any suggestions?

I noticed this on my toddlers arm this morning. He has one on his leg, a few on his other arm, and a couple on his knee. Any idea what this is or bite this is? We bed share and I don't have any bites or bumps on me. I was also sitting in the living room with him and still nothing on maybe looks like mosquito bites, but that's a lot of bites. Any suggestions? Bites/bumps are only on exposed skin