Did the dr recommend no filler? Filler for volume loss, otherwise the scars will re-tether again and subcision doesnt help much.
CO2 was useless, as BA would say: you dont pave a new road without fixing the potholes first.
Useless for you, $$$ for the doctor though. It's not a very good picture but it looks like a lot of volume loss. So definitely filler with subcision.

@Mindful13

Thank you for providing the picture, helpful.

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I have already undergone 3 subcisions (without filler) and a CO2 fractional treatment (Ultrapulse) and was wondering what I could do to improve this scar. I have already noticed substantial improvement overall on my other scars. However, given how bad this scar was (and still is), I would like to undergo additional treatments to get some improvement.

Ok first of all no filler after your subcision, ... the scars will simply re-tether or get worse. We use filler after subcisions. Secondly one needs 4 > sessions of sub to treat a scar like this. Your scar needs sub according to the pic provided.

Your lucky that your scar is localized and one area.

This is mainly a rolling scars, box cars may be in the upper area of the pictures above the biggest scar, I cannot say blurry but I will keep that in mind below. You have hyperpigmentation.

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