There are practitioners performing needling procedures with so many untested substances! Unless your practitioner is thoroughly trained and educated, and can tell you exactly what those substances are, and how they work, think twice! Minerals, pigments, actives, iron oxides & color, preservatives, silicones, etc., don't belong under the skin! Some practitioners sanitize and re-use needle rollers... Think about that. Anything that may cause pin-point bleeding can release and spread blood-borne pathogens.
In my opinion, if you have any pre-existing skin conditions, inflammation, and scarring, hitting it with needles only increase the problems because your skin is not healing properly as it is. There are many forms of collagen, and when there is an assault or injury to the skin, the first/temporary type of collagen is tough and fibrous. Problematic and scarred skin doesn't heal properly as it is. Why do you want to add to it? When skin heals properly and is not aggravated or disturbed, over time the tough initial collagen is replaced naturally with softer, proper collagen... without the intervention of needles.
Micro-needling can put you at risk of acquiring, spreading, and pushing dangerous pathogens into the skin. Please...Never do this at home, either!