Calamine lotion contains Zinc oxide and Iron Oxide(5%) as main ingredients.
If ingested in large amounts, it can cause mouth and throat irritation, vomiting, abdominal pain,nausea, diarrhea yellowness of eyes etc but 5 ml should not pose a risk if child weight and age is more..
Give her milk to drink( not if vomiting) and meanwhile it is necessary to know her weight, age, time when it was swallowed in order to assess whether it is posinous or not in the given amount of 5 ml.
Another fact is that zinc oxide which is one of the main igredients of calamine lotion is not poisonous at low doses .
5 ml is a tea spoon full so usually there is nothing to worry about at this small dose.
Just to be on safe side you can contact national poison control center at
1-800-222-1222 for more information.