If you need to dye your hair, the interval between dyeing your hair should be at least 3 months, preferably in a professional barber shop. Do not bake oil one week before dyeing, and do not wash your hair on the day of dyeing. The oil secreted by scalp has protective effect; If the scalp has a wound ulceration, it is not suitable for dyeing hair; Do a skin allergy test 48 hours before dyeing hair; Before dyeing hair, you can apply emulsion or vaseline to the hairline and behind the ears to prevent the hair dye from contacting the skin and causing damage. If the scalp has slight adverse reaction when dyeing hair, it should be stopped immediately.
If you wait in a smoky environment for a long time after dyeing your hair, you should wash your hair frequently and remove the harmful substances adsorbed on your hair in time. It's best to wear a hat when traveling in foggy days, and take off your coat immediately after entering the house to reduce the harm of dirty outdoor air to your body.