Thank you for your question. Silicone gel will not build new collagen. It will help flatten and soften scars and help with the coloring. I would not recommend silicone gel after micro-needling as it would not provide any extra benefits. Some things to look into to help build collagen is micro-needling, PRP (platelet-rich plasma), and ultherapy followed with a good skin care regimen. These options will depend on your concerns and skin problems. Vitamin C will help maintain good skin and help give some protection to your skin from what the environment can do to it. Consult with a reputable dermatologist or cosmetic/plastic surgeon who can provide you with all your options to give you the best results.