Scalp pain after hair coloring is contact dermatitis caused by hair dye irritating the scalp, which is more common in real life. Hair dyes are chemical products, and there are many people who may have an allergic reaction to one of the ingredients in them, and in severe cases, erythema and oozing may occur, leading to itching and pain. In this case, it is recommended to rinse with plenty of water to minimize the continued irritation of the hair dye on the scalp. If there is still no relief, you can consider topical medication, such as skin lotion or dermatological lotion with water, usually 2-3 days will gradually relieve. If still not relieved, or the symptoms are more serious patients, can be combined with antihistamine medication, such as levocetirizine hydrochloride tablets or diclofenac tadalafil tablets and so on. In the future, it is important to note that this brand of hair dye should not be used again in the future, as using it again will result in the same allergic reaction.