Whenever a Player's wound develops an infection, the infection will make the Player sick over time. The more infected wounds a Player has, the faster they become sick.
If the wounds are left untreated, the sickness will eventually become deadly.

Wound infections are divided in grades, based on how long they have existed for.
There are 3 grades: Low, Mid, and Severe. Each grade can be treated with certain medications.

By default (This is configurable), any infection will immediately start at low grade.
The Player can treat infections of this grade by applying alcohol wipes and alcoholed cotton balls. It is also possible to treat low grade infections with medications of higher grade, such as disinfectant or antibiotics.

An infection will become mid grade after it has existed for about half a day.
The Player can treat infections of this grade by applying disinfectant over the wound.
It is also possible to treat mid grade infections with medications of higher grade, such as antibiotics.

If a Player is hit by a projectile from a gun, there is a 30% chance (This is configurable) that the body part hit by the projectile will have its bones fractured.

It now takes about 2x as long to heal from any wound. For fractures, this time has been increased by 5x.

You can tweak this mod to your liking using sandbox options.
Some of the options include whether bullet wounds cause fractures, how quickly and how much sickness develops from infected wounds, how effective treatments are, etc.