How do I eliminate my chin from protruding and pointing out/down when I smile? (Photos)

Dynamic problems that are worsened with muscle movement are improved with neuromodulators such as Botox. However, the single lateral photo that you posted shows a prominent soft tissue chin pad which can be reduced and re-positioned or tucked. In addition, submental and jawline liposuction would give you a well contoured and youthful jawline. This procedure can be accomplished in the office with local anesthesia   

I would injected few units of neuromodulators in the mentalis as well as using fillers like Radiesse to augment and make the jaw more stronger than the chin and that would help with this issue.