Although LighSheer Duet is FDA approved for all skin types, the 1064 wavelength is best for dark skin types
I don't know exactly how dark your skin is. Types 5 and 6 should probably be treated with a 1064 YAG laser for the safest treatment. The 4.5 setting is extremely low and it will take several treatments to get results with that level. The underarm is less sensitive than the bikini area. I wouldn't use topicals because pain is an important feedback so the laser doesn't treat too aggressively. Other docs will have different opinions, this is mine. Steve Weiner, MD, Facial Plastic Surgeon, Destin.