My grandson has had some vomiting and liquid stools for 2 days with a low grade fever. His mom and baby sister have had the same thing. He woke up this morning feeling better and felt like eating for the first time. I fixed him a smoothie and he kept it down and was asking for another one about an hour later and feeling much better. He kept the second smoothie down. then he wanted some apple cinnamon cereal with milk. He ate just a little bit and has kept all this down but about an hour ago he broke out in big hives on his right cheek, upper back, around his belly button and his legs from the knees down to his ankles. I gave him 2 tsp of Benadryl. Should I take him to the urgent care to be checked? He will be 6 years old in 2 weeks