My Sons Bedroom Lamp Has Melted As Someone Had Placed

My sons bedroom lamp has melted as someone had placed an electric light up Disney hat on the top he was asleep in bed and when I went upstairs I could smell it the lamp had not set on fire but had melted the shade and the inside of the hat are these fumes toxic to my son I've opened the window and let some air in but I am worried for him o sleep in there ?