Oh this is interesting. I like to get Sarah's insight on this, too. I mean, what if the ice-pick scars are deeper than the needle can reach and prick?
But perhaps for light to mild cases, derma roller can be more convenient.
On Acne.org, there is a specific page that tell you the treatment that works for ice-picks scars and boxcar. LINK
. Though, it is intereseting to note that this website does not recommend skin needling for boxcar and ice-picks, but only for rolling. You should check the user reviews of each technique on that website!
[Update: there is a video on youtube about derma roller and ice-picks scar. Just so you know it talks of claims, not studies]
[Update 2: if you want word from a well known dermatologist on acne scar treatment, you can read this article by DERMAdoctor
[Update 3: you know. I think you should get a "good" result if you have a series of superficial or medium chemical peels in conjunction with derma rolling. Don't derma roll right after a peel, of course! With (very) deep ice-pick scars, I think you have to be patient with derma rolling because it can take several treatments to get plumbed up with new collagen. I think you need to consider prepping your skin and have a collagen-building/maintenance skin care routine after derma rolling like vitamin C and vitamin A or retinoid and copper peptide! And don't forget sunscreen!]