Hair toner is typically used to neutralize or correct unwanted tones in the hair, such as brassy or yellow tones. It is generally applied to the hair shaft and not directly to the scalp. However, if the toner comes into contact with the scalp, it may cause some irritation or discomfort.

Hair toners usually contain chemicals such as ammonia or hydrogen peroxide, which can be harsh on the skin. These chemicals are used to open up the hair cuticle and allow the toner to penetrate and alter the hair color. While they are generally safe to use on the hair, they can cause irritation if they come into contact with the scalp.

If you experience any burning or discomfort on your scalp after applying a hair toner, it's important to rinse it off immediately and discontinue use. You can also apply a soothing and hydrating scalp treatment to help alleviate any irritation.

To minimize the risk of scalp irritation, it's important to follow the instructions provided with the hair toner and perform a patch test before applying it to your entire scalp. This involves applying a small amount of the product to a small area of your scalp and monitoring for any adverse reactions for 24-48 hours.

If you have a sensitive scalp or have experienced previous reactions to hair dyes or toners, it may be best to consult with a dermatologist or hair care professional before using a hair toner. They can provide personalized advice and recommend alternative products that may be better suited for your needs.