Hi my son was prescribed cefizil 7 days ago, Today the doctor said to stop taking it because he had been misdiagnosed. His last dose was this morning around 7:30 am. Around noon he broke out in a rash. it started as small bite looking marks on his back, but soon spread to his buttuocks, legs and arms. I gave him 5 mls of Benadryl at 7 PM, he had a bath and fell asleep. He is still sleeping, but tossing and turning and wakes up crying that he is still very itchy and does not feel well. Some of the rash is now welting. Should we go to Emerg? Should I give him more Benydryl. He is 9 years old.