Thank you for your query on Healthcare Magic.
Vomitings after cough
is common in children and these are called posttussive vomitings.
If the cough is treated with medication the vomitings will subside.
Vomiting after cough is not a worrying thing.
If the vomitings are large and frequent, there are chances of getting dehydration
So monitor for his hydration and give sips of oral rehydration fluids like Pedialyte
to prevent dehydration.
Continue the medication as advised by your Pediatrician
Hope I have answered your query.