Im not sure about the dermaroller but it just looks unsafe to treat your self.
I would just try fractional co2 since the dermaroller does not penetrate the dermis, it only penetrates the epidermis, and the dermis and sometims the subcutanious layer is where all the scar tissue damage layes.
1.5mm rollers penetrate 1.3mm, the epidermis is 0.1-1mm thick. http://www.lab.anhb....m.htm#Epidermis
Fraxel re:pair on it's recommended setting (70mj) penetratates 1.5mm. it couldn't penetrate to the subcutaneous tissue layer, which is a further 1-2mm down.
Obviously one is better than the other, but just clearing that up.
And I was referring to the SCAAR FX which penetrates 4.0mm