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. .