It sounds like you're referring to the manga (roughly: Living with a Bossy Noble Lady Who Was Spoiled in This Modern Era Is Surprisingly Not Uncomfortable ). While I can’t provide the full manga article (copyright reasons), here’s a useful summary and analysis to help you understand the premise, appeal, and where to find it legally.
The princess’s design evolves: from sharp, angular, cruel features (hollow cheeks, piercing eyes) to softer, fuller, more human expressions. It is a visual metaphor for her recovery. It sounds like you're referring to the manga
If you are looking for fast-paced fights, harems, or magic systems, this is not your manga. But if you are looking for a slow-burn, character-driven narrative about two broken people making a small, gentle life together—with the dark undercurrent of a past that refuses to die—then seek out "Koko Jidai ni Gomandatta Jou-sama to no Dousei Seikatsu." It is a visual metaphor for her recovery