Hi, my son is 3 years old. He developed hives all over his body after completing the Amoxicillin course for ear infection and severe cough. I've been giving him Benadryl 5ml every 6-8 hours but it doesn't seem to help him as he's waking up crying due to severe itchiness. The hives seem to have been spreading more rather than reducing. Is there any other medication I can give ? He's been taking Zyrtec for allergies too.