When you breathe in, air from the wound fills your cavity instead of air from your nose and mouth. Treatment is to cover the hole taped on three sides to allow air to leave but not enter. We covered burns, head, face, and neck injuries, and spinal injuries. Burns are no longer classified as 1st, 2nd, or 3rd degree, rather they are referred to as Superficial, Partial Thickness, and Full Thickness. Pretty much the same levels, just different names.
Burns are a horrible injury, more so after the fact than when they just occur.
The worst thing you can do to a burn victim is to introduce some kind of dirt or contaminate into the burn. The decontamination process is horrendous. Head, face, and neck injuries were mainly just more trauma stuff. Control the bleeding, maintain the airway, and don't try to put stuff back in that is protruding, in a nutshell. For injuries to the spine we learned how to do a manual c-spine to hold the patients head and immobilize the spine.