I have tried Microdermabrasion with crystals. I started off getting it done every 2 weeks ($85 each time...pretty pricey) for about 2 or 3 months and then I went down to once a month for a few months but it didn't help my scars. I have ice pick scars and a couple of boxcar type scars near my mouth (on both sides of my mouth). It did not help get rid of the indented scars but it did smooth out the rough skin nicely. After 3 treatments, it got rid of the red marks so my skin looked so much better plus the shadows from the red spots were gone so my scars didn't look as deep.
I have been dermarolling for over 2 years and that is what has given me the most results. You can literally see the new skin where it has grown. micro helped to smooth out the new skin because it was bumpy in that area.
It does take time to see results. I have a blog about it but can't post the link here but I have posted pictures of the results. It works.
What I learned from my experience is that dermarolling works great on icepicks and boxcar type scars and older scars. My new scars are harder to get rid of for some reason. I still suffer from cystic acne so I am always getting new scars but all the old icepick ones have filled in completely and I have one big scar (not huge but it was the biggest) that filled in by about 50%. I also have one rolling scar that has not filled in and a line scar that looks like a wrinkle (underneath my freakin smile line so it looks bad when I smile and makes my smile line look longer) that has not filled in at all.
I just discovered that it works great on wrinkles too. I was not able to roll the left side because of a cyst that never went away but I rolled the other side and included my smile line. Well, the smile line on the right side is almost gone but the left side is deep so yeah I look uneven now. lol Oh well.