What will the doctor say if my mom asks about my pap smear results? I'm under 18 years old.

Emancipated minor. State laws vary. In most states, minors (<18) are not emancipated unless they are pregnant. However, you should not have had a pap smear unless you are 21. For several years, it has not been recommended for younger patients to have paps regardless of when they began sexual intercourse because they are much more likely to clear the hpv and the hpv effects.
Depends on location. It may depend on the state you live in, but in california girls under 18 have privacy rights with regard to reproductive care, so a patient would have to give permission to share results with a parent. State specific laws should be checked however.