is viral infection and it is self limiting.
It will take 6 to 8 day to disappear if child have not got secondary bacterial infection.
It required supportive treatment only.
I would advice:
keep her/ him Hydrate. Is most important condition.
1.Give plenty of water(1/2 liter water+ 4 tsf sugar+ 1/2 tsf salt) Or ORS
2.Coconut water, lemon water Butter milk, Rice Kanjee,etc
3. Proper hygiene.
4 Avoid out side food.
"I Wish She/He will Recover Soon "
Regards Dr. Sagar Mhatre