First, you must do a skin patch test before dyeing your hair, that is, apply a small area of hair dye on your wrist or behind your ear, and dye your hair again after 24 hours. There is no allergic reaction such as redness, swelling and tingling. Follow the instructions when dyeing your hair. Wear latex gloves if you dye it yourself.
Second, don't use different brands of hair dyes at the same time. There may be chemical reactions between hair dyes, which will produce toxic substances and increase the probability of allergies.
3. Rub some vaseline on your scalp before dyeing your hair. If you get it, it's easy to wash off. It is best to apply the hair dye at a distance of 1 cm from the hair root to reduce direct contact with the scalp.
Fourth, wash your hair several times after dyeing, and don't let the hair dye remain on your hair; Be careful not to scratch your scalp when washing your hair to avoid poisoning.