Guide to which LED light works best for each concern. Blue light for acne targets C. acnes bacteria. Red and infrared for wrinkles stimulates collagen. Red light for pigmentation reduces inflammation. Why multi-wavelength masks work best. How to choose a device. Results timeline: 2 to 4 weeks for early results, 6 to 12 weeks for visible results. Frequency: 3 to 5 times per week for 10 to 20 minutes.