Trichloroacetic acid (TCA) peels are chemical peels which exfoliate more deeply into the skin than over the counter acids. TCA is commonly used to treat sun damage and wrinkles.
Resorcinol is a chemical exfoliant which is commonly used to help treat acne, dermatitis, psoriasis, and even calluses and warts. Resorcinol sloughs off the dead layers of skin, and may lead to redness and peeling of skin.
The end goals for both TCA and resorcinol are to exfoliate the dead skin cells at the surface of the skin, and increase collagen production, leading to glowy, young, healthy skin.
Both TCA and resorcinol are professional-grade ingredients. I only suggest using these ingredients in a treatment from your skincare professional, or as directed when prescribed by a medical professional.