Hi,
Atrophic scars on the tip of the nose (from acne or chicken pox) is most challenging to treat due to the median location and convex surface of the nose which exacerbates the cosmetic appearance of the scar.
The highly sebaceous nature of the nose makes filler and subcision non-ideal.
In my opinion, Fractional CO2 laser therefore offers the best benefit:risk ratio of the 3 treatment modalities.
Hope this helps!