It could mean trying to understand the words of a novel by reading the lips of someone who is narrating it. However, it's a rather unusual concept as novels are typically read silently or aloud by oneself.
It might also represent suppressed emotions. For example, if a character has feelings for another but can't express them openly in the Fairy Tail universe, biting their lip could be a way to hold back those strong emotions. In some fan-created stories, it's used as a subtle sign of a character's internal struggle between what they want to do and what they should do.
Burnt oil has no ability to cure mange. Mange needs professional diagnosis and treatment from a veterinarian. They will determine the best course of action based on the severity and type of mange.
Yes, it can. Tea tree oil has some properties that may be beneficial in treating mange. But it's not a guaranteed cure and might work differently for each case.
Motor oil is not an effective treatment for mange. It's not designed for that purpose and can be harmful to both the affected animal and the environment.