... scar,pimple scar,severe decline of elasticity,etc) 3,How to use:Follow 3 steps of needling to enhance forming channelsHorizontally- ... minutes with 75% alcohol,Or use ultraviolet to disinfect for about 45 minutes.Do not use autoclaves,steam and high temperature sterilization ... methods5,Caution1)Don't re-use head2)Do not share with other person3)Do not roll too much more than ...