Daily before bath, for a minute or two, massage the neck area with downward strokes one hand following the other using any cream or skin oil. Apply lemon-turmeric paste on the neck to eliminate the colour difference in face and skin. Using yoghurt can also help remove the tan on the neck. Apply a layer of yoghurt over the neck area. Leave it on for around 20 minutes and rinse with warm water. Apply some regular moisturiser and massage gently. Use a natural scrubber on your neck daily to keep the lymphatic glands active and also to remove dead skin. Buttermilk is a very good cleanser for the neck, especially for those with oily skin.
Neck is prone to getting tanned very easily. So during the time of sun-bath you need to take good care of this part of the body and protect it from direct exposure to sun. A wide rimmed hat will save your neck from direct exposure to sun. But it is better to use a high factor sun block cream.