Will Cosmo Peel Treatment For Hyperpigmentation Cause Damage To The Skin?

Hello Doctor, my mom is undergoing cosmo-peel treatment for her hyperpigmentation area in the face. Already 3 sessions are over but there are no visible results and above this, she is experiencing a lot of itching and burning sensation even after 5 days of the service. I am worried about her. Will this cosmo peel treatment do any type of irreversible damage to her skin? She is around 50 years old. my email add is YYYY@YYYY