Newborn acne is a common condition caused by circulating hormones in the baby's blood. These hormones come from the mother, and generally disappear from the baby's circulation within several months. Newborn acne generally does not result in scarring, and treatment is unnecessary. In fact, applying substances to the skin can actually worsen the condition, which otherwise tends to disappear on its own in six to nine months.
Most important, kissing does not cause newborn acne. Don't hold back those smooches from your bundle of joy.