Hello there, An allergic reaction to advil is rare but the symptoms that you described seem to be allergy related. You can give a tab levocet to your grandson for the time being. This will reduce the rashes and the swellings. I know they appear scary but they will subside soon after taking this medicine. You can apply calamine lotion to the rashes too. It is soothing and will help your grandson. You have to give him fluids and try to make him drink a glass of water every hour. Stay off the advil(I think that is fairly self explanatory). Hope this helps, Please feel free to address further queries to me, I will be happy to answer them