Hello parent, I fully understand your concern.
Children usually get dehydrated, lose some weight during the chill phase but they usually gain weight in the convalescent phase. Please provide light balanced diet comprising of fruits, vegetables and grains..bed rest for some days. .
Rda of multivitamins is limited, and Overuse of multivitamins won't help..
Wait for some time.. Good luck
Next Steps
if possible please provide, age of the child, pre-sickness weight and post recovery weight, for better assessment.
Health Tips
consult for further evaluation