3year old hasnt peed for 5hours, has diarrhoea, chapped lips, two blisters on face?

Dehydration possible: He may be dehydrated, and he should see a physician. In the meantime, please provide fluids and monitor for fever. Pedialyte is one choice for hydration in this situation. Check his mouth for any blisters.

Some basics: A 3 yo is generally hydrated if they can pee at least once every 6-8 hrs & dehydrated if more than 10-12. Chapped lips & face blisters may be part of the illness. Small amounts of fluid/applesauce/ice chips given frequently can sometimes help a kid stabilize. if he spooks you have him seen.