Hello,
These red bumps can be due to contact dermatitis, insect bites, allergies or viral rashes. You need to take antihistaminics like benadryl or
Claritin. Longer-acting antihistamines are available by prescription. They cause less drowsiness and can work just as well. These medications include fexofenadine and cetirizine. But they should always be taken under medical supervision. Moreover you may try calamine lotion on the rash.