Hooley dooley pmastello....
If the machine was on all day, you are very lucky you didn't burn your house down. I am glad that you and the house are still here.
We had a client do this with her machine (switched on). Fortunately she was home to extinguish the fire but the resultant damage to the machine was terminal. If butter has dripped into the board and other bits, I'd be calling your insurance company.
Guys please- nothing other than dry cups should ever go on top of an espresso machine.