Final answer:
The most appropriate treatment is to apply an immobilizing dressing around the pencil and transport the child for medical care, as removing or pushing the pencil could cause more harm.
Step-by-step explanation:
The treatment that would be MOST APPROPRIATE for a child with a pencil impaled in the left cheek and penetration of the inner cheek wall would be to apply an immobilizing dressing around the pencil, and transport the child to a medical facility. Removing the pencil or pushing it through could cause further damage and increase the risk of infection and bleeding. It's essential to secure the pencil to prevent movement, control any external bleeding with gentle pressure, and quickly transport the child to a hospital for proper care by medical professionals.