Will UltraPulse work on tethered scars without subcision?

Acne scars are typically challenging to treat, regardless of the modality,
the best treatment is determined by the nature of the scars, whether they are icepick, boxcar, or more rolling scars. Subscision is more helpful for the rolling scars with a loss of volume.

Of course without photos, I can only comment in a general way. Subcision, which I have been performing routinely since 1995, is a simple, relatively inexpensive monotherapy treatment of choice for breaking up tethered, indented boxcar and rolling acne scars in order to elevate and smooth them. Subcison has a nearly three decades' long track record for both safety and efficacy in all skin types.
By contrast, C02 lasers, much like old-style dermabrasion, is a relatively expensive, essentially aggressive surface sanding process that not only engenders a prolonged post-treatment healing period and downtime, but risks scarring, skin discoloration, as well as the development of a permanent, unappealing, shiny, "orange peel" appearance to the treated skin. And other expensive, so-called "light and energy-based treatments," like fraxel laser and RF gizmos are backed far more by marketing hype and social media buzz, rather than any hard science. You would be wise to consult with a board certified cosmetic dermatologist scar treatment expert. And, one more word to the wise: don't go into any consult with requests for any specific "bells and whistles" treatments gleaned from Drs. TikTok or Instagram, etc. because, to your later disappointment, frustration and financial loss you are very likely to get what you ask for. Hope this helps and best of luck.