I appreciate your concern.
you have not mentioned is there any fever
or any other symptom,rash could be because of some allergy
,any viral infection,because of insect bite,or intake of some food,
i suggest you to apply calamine
lotion 3 to 4 times over red area,tell parents to observe child any in case baby does not improve take her to pediatrician
.she should also be kept at home till rashes subside.