Hello,
Nausea before
vomiting is usually associated with intense sweating.
You havent given your Son's age and what he had for dinner. Is it a routine dinner or something out of ordinary. Had food elsewhere,
Or did he had alcohol etc.
Vomiting may be induced by emotional factors (extremes), sight, thought of something nauseating. So it is not uncommon to find a reason even one exist.
If nothing significant happened also you may not worry if it has subsided.
If he is comfortable as of now leave as it is.
Ask him to drink plenty of fluids, since
dehydration may also cause vomiting. and ask him to take rest.
If it persist he may have
Emeset orally, if he vomits medication he may need a injection for vomiting.
Take care
Bye