If the case against a person found guilty of an offense under section 404 of the Controlled Substances Act (
21 U.S.C. 844) is the subject of a disposition under subsection (a), and the person was less than twenty-one years old at the time of the offense, the court shall enter an expungement order upon the application of such person. The expungement order shall direct that there be expunged from all official records, except the nonpublic records referred to in subsection (b), all references to his arrest for the offense, the institution of criminal proceedings against him, and the results thereof. The effect of the order shall be to restore such person, in the contemplation of the law, to the status he occupied before such arrest or institution of criminal proceedings. A person concerning whom such an order has been entered shall not be held thereafter under any provision of law to be guilty of perjury, false swearing, or making a false statement by reason of his failure to recite or acknowledge such arrests or institution of criminal proceedings, or the results thereof, in response to an inquiry made of him for any purpose.