how's the condition of your child now?
when i was a kid, i used to turn lobster very easily too and will start to "peel" in a few days' time.
My mom will then let me bring a bottle of sunblock , so i put it on before the activity .
prevention is better than cure mah....
then come back home, must drink lots of water.
Apply a bit of johnsons baby oil is good . ..the original pink bottle one. not the special fragrance (or added calming effect ) etc... I find that the bit of baby oil is more effective that moisturizer... you may want to try and see which is better.
must remember to have lots of water (or even barley water)... dont risk heatstroke!