How does SkinPen microneedling work?

Microneedling is great for smoothing out wrinkles, fine lines, acne scars, sunken scars, sun & age spots but how does SkinPen microneedling work?
Microneedling is great for smoothing out wrinkles, fine lines, acne scars, sunken scars, sun & age spots but how does SkinPen microneedling work?