Hi,doctor, My Baby Is 1.5years Old 10days Before My Son

Hi,doctor, my baby is 1.5years old 10days before my son had high fever and loose motion with mucus,after taking some medicine,fever has gone after 10days,but loose motion with blood was continued after taking econorm sachet the loose motion is remission but new problem is my baby have a skin red allery on body,i have use a calamine with alovera but alleric not cure,how it is cure.