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This intrigued me because of some of the slides she showed and also because my father, an acupuncturist, had a little device that looked a lot like that. I was also surprised to find, after talking to her after, that you can easily buy these devices online such as this FDA approved one here. I have ordered one and found it a little annoyingly painful on my face, but pleasantly tingly on my stretch marks and scalp. Too soon to see if it works BUT it's totally non invasive.
The other advice I received from the derm is to look out for the needle size. For the scalp you should never go longer than 1.5mm. For sensitive skin, you will need to go shorter, for results for tough stuff like stretchmarks, you'll need to go longer, up to 3.0 mm. Again, this is not medical advice but just passing on some kwoledge I picked up.
If anyone else tries this, please report back!