Dale says that 'anthemis nobilis' is the ingredient in chamomile tea that leads to allergic reactions. Anthemis Nobilis is in fact a strand of chamomile, meaning that Dale said that chamomile is the ingredient in chamomile tea that causes allergic reactions.
When Dale cuts Tucker down from the tree Tuckers hands go out wide to his sides. It is clear that he has all 8 fingers and 2 thumbs, despite the fact that two fingers are supposed to have been cut off.
When the sheriff arrives to question Tucker and Dale at the cabin, Tucker's face is still slightly swollen and covered in Mike's blood. When they go in the cabin to check on Allison, Tucker's face and neck are clean and un-swollen. When they go back outside after the sheriff gets hit with the beam, Tucker is bloody and swollen again.
When the one college kid jumps into the wood chipper and gets killed there is blood everywhere, all over the back of his pants down to his ankles and on his shoes. Then later on when Tucker and Dale are taking what's left of the body out of the wood chipper there is no blood on the shoes or on the bottom of the pants.
Near the beginning, the kids run out of the lake soaked and wet and screaming after seeing Tucker and Dale pull Allison onto their boat. They run and in a quick moment they see Chad and are completely dry, one even has her clothes back on.
Everything happens in one day - from the time Tucker is stung by bees, he has horrible welts on his face also cuts and bruises from everything else. The welts change from scene to scene from the start and quickly disappear. After an hour in, they crash their pick-up into a tree and when Tucker is talking to Dale, his face is clean like nothing ever happened - at all.
When Dale is making breakfast for Allison and putting the bacon on the plate and arranging the flowers in the tin can, the flowers are healthy and freshly cut and standing up straight. But in the next scene when Dale walks through the door to give the tray to Allison the flowers are all wilted and bent over and drooping.
Dale tells Chuck to check the safety when Chuck is pointing the police officer's gun at Dale and Tucker. Chuck is holding a revolver which does not have a manual safety lever. It is unlikely that Dale's helpful suggestion was actually a clever ploy to kill the young college kid.