The skin barrier is a wall of cells and lipids that keeps water in and irritants out. Over-cleansing, over-exfoliating and cold wind all chip at it. When it is compromised, everything stings and nothing seems to hydrate.
Repair is unglamorous. Stop all acids and retinoids for a fortnight. Cleanse once a day with something gentle and low-foam. Layer a humectant serum on damp skin, then seal with a ceramide cream. Add squalane on the worst days.
By week four the stinging fades; by week eight the barrier holds again. Then reintroduce one active, slowly. The patience is the treatment.