A dismissal is when the prosecutor decides to drop the case. Sometimes a dismissal comes after the assistant district attorney reviews the evidence and decides that the case is not strong enough or not worthy or prosecution. Other times, a dismissal is a reward for performing community service or attending abuser treatment classes or drug treatment. If you have a case dismissed, someone may still be able to find out about that case. If an employer does a criminal background check, your record will show that you were charged but that the case was dismissed. Remember: If a case is dismissed against you there is NO criminal conviction.
An expungement is when all traces of the charge are erased. The court records are supposed to be destroyed as are any records that the police have. North Carolina law typically allows one expungement per lifetime. If other cases are later dismissed, evidence of those dismissals will show up on your record.