Dear Abby: I didn’t steal from my mom. How can I convince her to let it go?

Dear Abby: My mother has accused me of removing personal papers from her file cabinet. I have never gone into her file cabinet, nor have I ever removed any papers. This accusation is extremely hurtful. It has strained our relationship. I place great emphasis on honesty and integrity. I am now considering taking a polygraph test to validate my defense. Should I follow through or just let it go? — Honest Daughter