I am babysitting an 18 month old boy.  He had a runny nose last week (somewhat normal) and a rash in the lower abdomen and diaper area with blisters that burst and red dots  (no scabbing).  Today the rash has spread to his thighs and upper abdomen, but no blisters so far.  His pelvic area is swollen, but not his testicles or penis.  No fever.
Hi, This can be diaper rash or even due to fungal infection. If you can upload a photo of the rash we can help you in diagnosing and treating it better.For now don't use diaper for a couple of days, keep the area Chat Doctor.  Use only cotton clothes sun