Mass. Gen. Laws ch. 94C § 44
If any person is found not guilty of the violation of any provision of section thirty-four or if a complaint against him is dismissed or an indictment nol prossed for a violation of said section, the court shall order all official records relating to his arrest, indictment, conviction, continuance or discharge to be sealed; provided, however, that departmental records maintained by police and other law enforcement agencies which are not public records shall not be sealed.
No person as to whom such sealing has been ordered shall be held thereafter under any provision of any law to be guilty of perjury or otherwise making a false statement by reason of his failure to recite or acknowledge such arrest, indictment, disposition, sealing or any other related court proceeding, in response to any inquiry made of him for any purpose.
Mass. Gen. Laws ch. 94C, § 44