In some TV prints, the part where the dog fetches the stick of lit dynamite thrown by Bugs, and sustains the explosion while the dynamite is in his mouth, is removed in such a way that the dog seems to have acquired the consequent cuts, bruises, and powder stains simply by falling from the air in his chase of a balloon bunny (that Bugs had released in a prior act of heckling). Hence, there is no explanation for the charred remnants of a red dynamite stick in his mouth.
Paraphrased from: The Censored Cartoons Page