It seems you’re looking for — likely the manga by Suzue Miuchi.
On November 14, 2025, Hana to Yume magazine (the series’ long-time home) dropped a bombshell. Issue #24 featured a full-color insert: "The Final Curtain Rises." Suzue Miuchi, now in her 70s, had apparently resolved to finish the saga.
The title refers to the "mask" actors wear; it is as fragile as glass because any lapse in concentration can cause it to shatter, exposing the actor's true self.