Q. My 18-month-old granddaughter has clear blisters under her bottom lip, inside of her mouth, on her tongue and under her tongue. She hardly eats because it hurts. What could it be?

A. My first thought is that this is a viral infection. This is very common in childhood. The initial infection of fever blisters or cold sores often looks like this.

These viral infections are always self-limited. Meaning that by the time you read this (they are usually gone in just a few days), she will be fine. If it lasts longer than a few days she should see the doctor to see if it is something other than a virus.

In the mean time, it is important to make sure she stays well hydrated. It is easy for a young child to become dehydrated when she is unable to eat or drink. One trick is to use popsicles since the cold is usually well-tolerated by the sore mouth. At least that is one way to get some fluid in.

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