Micro-needling can be safely repeated every 4-6 weeks as needed. Collagen induction requires at least 3 treatments, while scar reduction requires between 3 and 6. 4 to 6 weeks should pass between one treatment and the next, and the number of treatments needed depends on individual cases. Micro-needling can be used on all parts of the body (neck, décolleté, arms, legs, etc). Usually results begin to appear after the first treatment.