Your 16months kid is having papular eruptions speading allover as you said. The papules are skin lesions that are raisedfrom surface and are small sized, solid to feel, if they are fluctuant-having fluid then they are called pustule- layman termfor them is pimple.
I think your child has got Papules and not pimples
as you have told and the most likely the problem is Molluscum
Contagiosum- It's a self limitting viral disease, would heal by itself without sequelae but it can spead to other children through touch so isolation is required for two weeks.
If the eruption is pustule and is painful and child is having fever
also then it is chickenpox
but I do not think that is the case.
Methinks that solved your query.