Yes, you can use toner and lactic acid together in your skincare routine. However, it is important to consider the concentration of lactic acid in the product and the sensitivity of your skin. Lactic acid is an alpha hydroxy acid (AHA) that helps exfoliate the skin, improve texture, and promote cell turnover. It can be found in various skincare products, including toners.

When using toner and lactic acid together, it is crucial to follow a few guidelines. First, start by introducing lactic acid into your routine gradually, especially if you have sensitive skin. Begin with a lower concentration and gradually increase it over time as your skin adjusts.

Second, avoid using toners or other products that contain additional exfoliating ingredients, such as salicylic acid or glycolic acid, at the same time as lactic acid. Using multiple exfoliating products simultaneously can potentially irritate or over-exfoliate the skin.

Lastly, always remember to follow up with a moisturizer and sunscreen during the day when using lactic acid, as it can make your skin more sensitive to the sun.

Overall, using toner and lactic acid together can be beneficial for improving skin texture and promoting a smoother complexion. However, it is essential to consider your skin's sensitivity and introduce lactic acid gradually to avoid any potential irritation or adverse reactions.