I know of no "legal" prohibition against recording a teacher's lecture. However, there may be rules or policies the school district has adopted prohibiting that.
Mississippi is a "one party consent" state. That means that as long as one party to a conversation consents to the recording, it is legal. The "one party" can be the person who is doing the recording.
In your case, because the student obviously consented to the recording, there is no violation of the law.
Mississippi Criminal Defense Lawyer
Offices in Jackson and Gulfport
While Mississippi allows one party to record another ,your question involves giving the recording to another for their use,and that may be another issue.Please contact an Attorney for a better and more complete answer before the recording is used.
781 Liberty Rd.
Flowood Mississippi 39232