Hi,i understood ur question as well ur problem.ur child has how many times vomited that is the main point accorind to that u cn give medicines..if he has vomiting once or twice u give emeset 6ml twice..if its more u cn give trice or depending upon frequency u cn increas if needed.u stop giving all outside foods or any etables to him.give home made food items nly like khichdi(ganji),boiled sabudana ,fuit juices,electrol ,glucose water,nimbu pani etc.use only boiled water fr drinkng.give electrol(newly came apple flavor)as much as he can take that will help in preventing dehydration .as u told u hav to attend a function today,i will advice you to escape it if its possible.if not u attend the function but dnt give anything to ur child in function.take food from home for him then go.otherwise it may worsen his condition.if any other query come back to me.wish your child good halth.