I treat them the same way that I do uninjured characters.
if it's important to the story it takes more time.
In the Seven Forges series, where, frankly, injury and death walk hand in hand along the main road of life, several of the main characters are injured, some of them severely. Merros duller suffers from saddle sores and one knife wound. I mention both in passing. Every member of the Sa'ba Taalor look at their wounds earned in battle as victories: they survived, you see, and most of the time their enemies did not.
In the case of Andover Lashk, his first appearance in the book results in both of his hands being ruined with a blacksmith's hammer. Everything that happens to him after that moment is shaped by those injuries. There isn's a scene with Andover where the memory of his ruination does not linger. Every action, every reaction, every change in his character through the course of four novels is seen through a lens of violence and the memory of what was done to him.
Drask Silver Hand has a hand that is forged from silver. It moves, it lives, it is a part of him but how that and was lost and what he did to earn the replacement are a part of him and, like his scars, shape him.
Injury and violence are a part of the culture of the books I wrote. They are integral to the story on many levels. The more scars a Sa'ba Taalor has that have been earned in combat, the greater that warrior's prestige. To them the idea of living a life without scars is like living a life as a street beggar. They don't care about wealth. They don't worry about creature comforts. They worry abut serving their gods and the gods they worship are gods of war.
In other books the actions are different. It depends on the circumstances. Mostly, however, and this is important to me, I consider injuries like every other facet of a character. They are either part of the force that shapes the character or they are mentioned in passing. Whichever works best for the story in question.
Drask Silver Hand Lost his hand in combat.
King Tuskandru has massive scars around one forearm from when a chain tore across his flesh. His enemy did not survive the encounter.
Swech is covered in scars. She healed, her enemies did not.