The Norbit star was taking part in a charity race at the Irwindale Speedway in California when he lost control of a pal's sports car and crashed into a wall.
Griffin blasts, "You got crazy conspiracy theories that think it's a hoax...The pain I got in my neck is not a hoax."
The comedian insists he could never crash such an expensive vehicle just for a publicity stunt: "How retarded do you got to be to think that somebody is going to wreck a million-and-a-half-dollar car as a hoax?
"Why would I want to be the one driving it and running it into a concrete divider as a hoax?"
Griffin has cancelled commitments for two weeks to allow him time to recover from the crash, and he tells news show Access Hollywood the accident has taught him a lesson.
He adds, "I shouldn't be behind the wheel in a car race... We will stick to microphones."
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