My dryer has not been used in 2 days because it was so hot you couldn't touch it. So, My fiancé unplugged it for a day and a half. He plugged it back in today and not 20 min. after it was warming up? Does anyone know what it wrong with it?

There could be a minor short that is causing something to bring the elements on. Without a close visual inspection and using a meter, there is no telling exactly what the issue is. Unless someone is mechanically inclined and knows what to look for and how to use a multimeter, best to call in a pro for this.