TCP liquid can cause irritation and dryness to the skin when used repeatedly or in high concentrations. It may also cause redness, itching, and burning sensations. In rare cases, it can cause more severe reactions such as rashes, allergic reactions, and contact dermatitis. To avoid these side effects, it is important to follow the instructions on the product label and avoid prolonged contact with the skin. If irritation occurs, rinse the affected area thoroughly with water and seek medical attention if necessary.