Can your dr report you to CPS if your child has a severe open blistered diaper rash?

It would depend on the reason for the rash. Is it just because of neglect and letting baby sit in a dirty diaper? Could baby have a yeast infection? Perhaps he is teething. If it is neglect then a doctor has an obligation to report, but as a medical professional a doctor should be able to tell if there is a legitimate reason for such a rash.