My two year old son had amxcillian for a infection and has been off of it for less then a week, he deploveld a rash his doc said it was from the drug, but its almost been a week (3 days shy) and it seems to have had hardly faded on his body and now the rash on his face has turned into almost like under the skin blood blister. And it on his cheeks and around his mouth. What could it be? He has a cough but nothing else is wrong..