More than two years ago, when Allergan inked a $2.1 billion pact for Kythera, Bernstein analyst Ronny Gal wrote to clients that Allergan "obviously" has "much higher expectations than we do" for chin-fat drug Kybella. And for some analysts, that’s never been more true than right now.

Earlier this week, Credit Suisse analyst Vamil Divan slashed his peak sales estimate for the chin fat-buster to about $100 million—far below the $400 million analysts projected back when Allergan made the pickup.

The reason for the tweak? Divan pointed to "the limited commercial progress that product has made"; in the third quarter, Kybella racked up just $11.2 million in revenue, bringing its haul for the year so far to $42.5 million.

Analysts had some concerns about Kybella from the get-go, despite Allergan's claim that the product could eventually rival blockbuster Botox. As Evercore ISI’s Umer Raffat pointed out at the time, Kybella posted a 4% incidence of facial nerve injury in trials. And Gal, "looking to fillers as an example," predicted that Kybella’s rollout would be "slow."

"Products with this treatment profile are not ideal candidates to be big sellers," Gal wrote to clients at the time.

The way Allergan commercial chief Bill Meury sees it, though, Kybella is still "strategically ... very strong."

"There's a lot of training still happening, and physicians are learning how and where to use the product to selectively reduce fat," he told investors on Allergan's third-quarter earnings call, adding that as the body contouring market continues to develop over the next several years, he expects to see the med become "a steady contributor."

If it can’t, Kythera may just become a stain on an Allergan dealmaking record that has otherwise looked pretty good as of late—at least where marketed products are concerned. The company last year hived off its generics business in a $40.5 billion sale to Teva, narrowly escaping from the pricing pressure that has slammed industry players and decimated Teva’s shares.

And on the aesthetics side, this year’s $2.5 billion purchase of Zeltiq and its CoolSculpting system has already started paying off. CoolSculpting is "exceeding expectations" in the U.S., Meury said on the call, with 3,100 of Allergan’s top 10,000 medical aesthetics accounts already using the fat-freezer.