Does microneedling help brighten the skin?

Yes, but it is important to clarify what you mean by "brighten". It will improve your acne scaring, brown spots should lighten and with texture improvements, your skin will often brighten!

Microneedling helps to improve the skin texture, fine lines, pigmentation, and scars. This happens because fine channels are made into the skin with resulting stimulation of high-quality collagen. New collagen will make the skin appear more radiant. But for better results I use new-generation chemical peels or laser and depending on the skin condition might suggest using a combination of therapies.