Suggest Treatment For Diarrhea And Diaper Rashes
I have gone through your question and understand your concerns. Do not worry. The treatment with Gatorade is not appropriate for an episode of watery diarrhea. It can lead to electrolyte disturbance (dyselectrolytemia) like hyponatremia and hypokalemia. Abdominal distention in your child seems to be due to dyselectrolytemia.
As it is associated with lump next to navel the condition needs proper clinical evaluation to rule out lymphadenopathy or paraumbilical hernia. So, I would recommend you to visit a pediatrician for complete clinical evaluation and investigation.
At present, start him on oral rehydration solution along with balanced healthy diet.
Hopefully it will be of help.