Easy. Just knock it off. It's completely in your control. Block her.
When you are tempted to unblock, or to use another profile to look, STOP. If you have to, wear a rubber band on your wrist and snap it HARD. Aversion therapy.
If that doesn't work, get off Facebook altogether. It's not required for a happy and healthy life.
It won't take long for you to realize that you feel MUCH better when you don't pick the scabs.