Dell 5480 Smoking and Melted Plastic

I was usingy Dell tonight and my friend saw it smoking and I started to smell burning plastic . I immediately shut off my computer and unplugged the charging chord, and when I turned the laptop over I saw where the plastic had melted because the computer got so hot. I don't know what to do in this situation, but I'm afraid to open it because I don't want it to start smoking again.