Respiratory system: smoking irritates the windpipe and voice box. The lung airways will also swell and narrow, and there will be excess mucus in the lung passages. It also affects the lung's clearance system, which may lead to toxic buildup.
Circulatory system: There will be raised heart rate and blood pressure. Blood will also become stickier and more prone to clotting. The lining of the arteries will also be damaged. Smoking will reduce blood flow to fingers and toes; will also constrict blood vessels in the skin.
Hope this helps! Have an awesome day.
I think it would be best to forgive the other person and move on as she'll still have a feeling of resentment if she writes about her feelings and doesn't forget about it.