Mass. Gen. Laws ch. 231 § 93
Where the defendant in an action for libel, at any time after the publication of the libel hereinafter referred to, either before or after such action is brought, but before the answer is required to be filed therein, gives written notice to the plaintiff or to his attorney of his intention to publish a retraction of the libel, accompanied by a copy of the retraction which he intends to publish, and the retraction is published, he may prove such publication, and, if the plaintiff does not accept the offer of retraction, the defendant may prove such nonacceptance in mitigation of damages. If within a reasonable time after receiving notice in writing from the plaintiff that he claims to be libelled the defendant makes such offer and publishes a reasonable retraction, and such offer is not accepted, he may prove that the alleged libel was published in good faith and without actual malice, and, unless the proof is successfully rebutted, the plaintiff shall recover only for any actual damage sustained. In no action of slander or libel shall exemplary or punitive damages be allowed, whether because of actual malice or want of good faith or for any other reason. Proof of actual malice shall not enhance the damages recoverable for injury to the plaintiff's reputation.
Mass. Gen. Laws ch. 231, § 93