Could Rashes And Itching Be Due To Adderall?

My son just started adderal 10 mg a blue pill a week ago and was taken 25 mg of focal in before this he seems to be in responsive and stares right through me if I ask him a simple question that requires a yes or no question. He never wants to go any where and acted the same way on the focal in. Someone told me that it will take several weeks for me to see a difference but I thought it was seen through each dose. Is this the wrong medicine for him or should I wait it out. Also for the last two days he has been itching with a rash but has several allergies so I am unsure if this is medicine or a reaction to meds.