17 month old in day care, red spotty rash on abdomen and back, spreading to arms and legs. temp 39.4 (17 days ago), think that was hand foot mouth?

Unlikely: HFM can have spots/blisters in these locations.However, the presentation usually starts with small blisters in the back of the mouth, followed by distinctive blisters (oval and grayish) located in other sites.The fingers/hand/wrist are common as are the foot and ankle.The peri-anal region is also common. The rash you describe is non specific and could have been many things,HFM is unlikely.