My Son Hid A Box Of Cliff Bars In The

My son hid a box of cliff bars in the oven. Weird place to choose to hide anything! but anyways , I came home and preheated the oven to 400. some of the wrappers began to melt , others did not even seem warm. My son, an adult, ate one whose wrapper had melted and said it was fine. I don't think that we should eat them. Are they toxic and should my son see a doctor?