So you dyed your hair, and now you also have a dyed scalp. This is fairly common for those who color their hair at home. Luckily, there are ways to rid your skin of the color.
Apply pasty toothpaste (gel will not work) to the colored skin. Let it dry. Then remove it with warm water and a clean cloth.
Rub nail polish into the affected area by applying it to a cotton ball. Rinse the area with warm water and dry it with a clean cloth.
Mix together equal proportions of baking soda and dishwashing liquid. Apply it to the dyed scalp with a clean cloth and rub it in. Allow it to sit for a few minutes. Then rinse the area with warm water. This is more likely to fade the color rather than completely remove it. So it should be used as a last resort.
Allow the stain to fade naturally as you wash your hair daily.
Avoid stained skin by applying Vaseline to all exposed areas.