What should be the punishment for lying about abuse (even hitting yourself and lying about it)?

Anonymous
I'm in a tough situation. My own sister confessed a secret to me just this Sunday. She pleaded with me to keep it quiet but I feel terrible now.

Way back in 2018, her ex boyfriend was supposedly arrested for domestic violence but released on the condition of no contact and finishing an anger management program. There was a small bruise on her arm too and back of her thigh.

Her secret is that she was upset upon finding out he cheated. She hit/spanked herself to make it look believable and faked it all. It was a lie that she was abused. She wanted to get back at him for cheating.
Updates
1 y
The subject about domestic abuse came out. I was saying something like ''thanks goodness you got out of that abusive relationship''. That's when she admitted the whole thing. Basically she lied to all of us too
What should be the punishment for lying about abuse (even hitting yourself and lying about it)?
6 Opinion