Collagen Red Light Therapy Red light therapy works from the inside-out to lead to several skin benefits. Red light decreases skin inflammation, smooths skin tone, repairs sun damage, fades scars and stretch marks, and even builds collagen in the skin, which reduces wrinkles. It also heals wounds and can prevent recurring cold sores or herpes simplex. Red light works on the lymphatic system to improve your body’s detoxification abilities by increasing blood flow.