Infection (5e Disease)
From D&D Wiki
If a creature is missing more than 5 hit points for more than 3 hours, they must succeed a DC 15 Constitution saving throw at the end of every other hour. On a failure, the wound becomes infected. This can be avoided by cauterizing the wound by having 5 fire damage be willingly dealt to the creature.
Stage 1: Upon becoming infected, the creature’s hit point maximum is reduced by the amount missing. This lasts until the infection is cured. The creature must succeed a DC 16 Constitution saving throw every 6 hours. After 3 failures, the infection develops into stage 2. After 9 failures, it develops into stage 3. After 15 failures, it develops into stage 4.
Stage 2: The infection spreads from the wound across the limb. They have disadvantage on any checks regarding that limb, and attacks to that limb deal twice as much damage.
Stage 3: The infection enters the creature’s bloodstream substantially. The creature has disadvantage on all saving throws. Their hit point maximum decreases by 1d4 at the end of each hour.
Stage 4: The creature dies as the infection deteriorates vital organs and causes major blood loss.
Infection can be cured with lesser restoration cast with a spell slot of 2nd level or higher or by amputating the infected area with a DC 15 Medicine check While wielding a weapon that deals slashing damage.