Highly concentrated hair dye is designed to dramatically change hair's natural color. This dye is especially damaging to the skin and hair if it's left on for too long, so it's important to ensure you remove all traces of dye from your hair and scalp. Darkly pigmented dyes that are left on for too long might temporarily alter the color of the scalp and the skin around the hairline.
Prep Your Hairline
Before applying dye to your hair, prep your hairline. Apply a layer of facial oil like jojoba, squalane or baby oil along your forehead, behind your ears and along the base of your neck. If you don't have oils, you can use petroleum jelly. Creating a layer of moisture around your hairline will keep the dye from soaking into your skin.
Two Wrongs Make a Right
If you have some dye staining your skin, apply additional dye on top of the stained area. Rub in the dye, which will reactivate the substance, making it easier to remove. Quickly massage warm soapy water onto the area, and remove the dye with a washcloth.
Apply a pinch of baking soda to the affected area with a few dabs of liquid soap and gently rub. Allow the baking soda mixture to remain on the skin for one to two minutes; then rub it off using a warm washcloth. Repeat until the stain is gone.
Dip a cotton wool pad in a bowl of vinegar and rub on the stained area. The cotton pad has an exfoliating effect and will help to remove dead skin cells and the dye stain.
If your entire scalp has been dyed by hair dye, removing the stain might also remove the hair color. Consult a hair stylist for help.