Suggest Treatment For Severe Ear Infection And Hives All Over The Body

My son just had an ear infection and had an alergic reaction to amoxicillin and was developing hives all over. They told us to put him on Benadryl And Claritin for that issue. Now he is complaining of leg pain , he woke up last night for a hour crying about foot pain but today was fine till this afternoon when he said his imaginary friend fell on him and hurt his leg. He won t move and went from sitting to laying. His left knee does look swollen and he doesn t respond negitive to his feet being touched and his behind. Could this all be connected?