The appearance of horizontal forehead lines is an inevitable part of the ageing process as we get older our body produces less elastin and collagen these two substances give skin its springiness and elasticity this causes the skin to become thinner as it gets older one of the most popular treatments to help reduce lines on the forehead is botox when injected into the skin botox causes the muscles underneath to relax making them unable to move in a way which produces lines or wrinkles th