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Also... this video, which is instructive for other reasons, also briefly covers blast damage from contact range gunshots:

I had a patient who was executed at contact range with a 12 gauge to the base of his neck. He was a long-haired blond white kid. The entrance hole was badly burned around the edges, and probably an inch and a half in diameter. The blast vaporized 2 of his cervical vertebrae. They had simply ceased to exist....along with a couple of inches of his spinal cord. The full charge went down into his left chest. When we cracked his chest, we found the wad sitting on top of his diaphragm. A good deal of his left lung was completely pulped. The miracle was that no part of his aorta had been touched. He was still conscious and talking upon arrival in our ER. His speech was a combination of wailing that "they" had killed him, and begging us to not let him die..... which was inevitable. Blood was pouring out of the wound. Over time, the bleeding got more and more pinkish as it became diluted by IV fluids, despite the transfusions he was also receiving. He was 19 years old. Police believed that it was retribution for a bad drug deal or something like that. His girlfriend said that there’d been a knock at their door, but she didn’t see who it was. She heard a quiet exchange of words, then the vic turned to her and told her that he had to step outside for a minute. A minute later, she heard the boom, ran outside and found him on the lawn, and called 911. He was conscious until just before we got him into the OR, and then he was gone.

It’s one of the cases that has lived in my head ever since. Contact distance gunshot wounds are no joke—especially from shotguns.