Lichenified means the skin has become thickened and leathery. This often results from frequently rubbing or scratching the skin.
Chronic irritation due to conditions such as eczema can cause lichenified skin. Moisturizers and topical steroids are usually used to treat lichenified skin. Any underlying skin condition should also be treated.
References
Dinulos JGH. Principles of diagnosis and anatomy. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 1.
Swanson E. Morphology of primary and secondary skin lesions. In: High WA, Prok LD, eds. Dermatology Secrets. 6th ed. Philadelphia, PA: Elsevier; 2021:chap 2.