What are neck lines? – Neck lines can appear commonly as part of the natural ageing process and are usually defined by wrinkles and sagging skin due to a loss of elasticity. As you age, your natural skin cell turnover decreases and the collagen that you naturally produce depletes.
These ageing wrinkles usually appear horizontally to your neck. However, you may also find another type of wrinkles, vertical neck lines. These are caused by keeping your head in the same position over long periods of time for example when working with a computer, or when you sleep. Treatment and prevention of neck lines – The neck is often one of the most exposed areas of the body and therefore it is important to protect it against damage. There are some steps you can take to reduce your chances of developing neck lines. These can also help you ease your discomfort from the ones you already have:

Wear SPF (Sun Protection Factor) sunscreen. Use an SPF of 30 or higher when you are outdoors, whether in the sun or not, as UVA light levels can cause damage throughout the year. Reapply every two hours if you’re swimming or perspiring.
Exercise your neck daily. This will tighten your neck’s muscles and pull in sagging skin a bit.
Use moisturisers products with built-in SPF. Though moisturisers can’t prevent wrinkles, they may temporarily mask tiny lines and creases. SPF will block both UVA and UVB rays.
Eat a low-salt diet rich in high-fibre foods.
Avoid smoking.