That's microdermabrasion and I wouldn't mess with hypertrophic or keloid because they can cause a depression if treated incorrectly. I would visit a derm or surgeon for this..

Check here:

Prior to the depression a keloid/hypertrophic scar was present.

There's other alternatives for such scarring for example silicone sheets and single needling then massaging the scars. Personally I have no experience and I recommend you have them examined by a trained professional before you decide to do such thing.

I have no professionals in my country...

They are really small. I don't even see them to needle, but I know they are there. It's hard to explain... I'm not a native, I'm sorry.

I rolled and stamped my cheeks about 4 months. They don't respond (btw, atrophic ones respond well). I really don't see any other ways to get them flatten, except dermabrasion.

In part of causing depressions, I don't think so. As I already said, they're small. But I'm afraid they will grow up again.