Bites that look like small blisters, all over my 2 year old. They are on his chest, back, arms, but mainly from where the elastic from his underwear sits on his hips all the way to his thighs. He has started running a low grade fever. Right at 100°.

Significant. These symptoms are serious for a 2 year old child. It is imperative that your child get to the pediatrician or dermatologist ASAP. Several causes are possible and need an accurate diagnosis.
Mgt. He should be seen today and evaluated for infections such as Strep or Staph.