love is miles away

(you do not have to follow the beliefs associated with the style if that style has associated beliefs. The wheel curse does not affect anything like that.)

Please imagine me gently holding your hands, I am not reprimanding you, I say this with nothing but love and respect, but

If you give a character with no access to antibiotics a wound infection, they are going to die.

If a character is delirious with fever, they are going to die.

Make them lose a substantial amount of blood. For reference: For an adult human, about 8% of their body weight is blood. They can lose around 10% of that without much trouble, 20% will cause serious symptoms, more than 50-60% is generally incompatible with life. These numbers are estimations. The slower this blood loss, the better the body can compensate for it. Losing a significant amount of blood will affect the character's consciousness and take days or weeks to recover from.

Fever and malaise. Injuries are stressful. Inflammation is a natural response to that. Destroyed cells release proteins which can cause moderate fever (too much of that can cause kidney failure which is why excessive beatings can kill people, even when they don't initially sustain any life-threatening injuries). The character will be in pain, they'll feel like shit, they'll need plenty of rest and tender caretaking without their limb rotting off.

If you have to infect them, give them an abscess. That way, the pus and bacteria are walled off and can be drained out (by cutting the abscess open), with lower risk of it getting into the blood stream. It's also risky but much more survivable than phlegmone (diffuse infection of soft tissue).

Drugs. Just drug 'em. Ye Olde Opium/Laudanum will put them in a scarily deep sleep while Love Interest can sit there and hold vigil. Now this might also kill them so use with caution.

Keep. It. Clean. Carefully and gently clean out gross stuff and things that do not belong in there, do not introduce foreign matter, and keep that wound covered.

The body will support Caretaker in this. Exudation is a natural defense mechanism to flush out germs and other dirt. Normal exudate is clear, with a slight yellow tinge, and almost odorless (wounds do have a characteristic smell, but they don't stink). Excessive exudate can form crusts around the wound, those should be cleaned away. Boiled water or saline solution is probably the safest bet for wound irrigation. Gentle mechanical cleaning (wiping with wet cloth) is appropriate.

Wounds want to be kept moist. Ointment can help with that, and also prevent the bandage from sticking to the wound. For a premodern setting, lard (rendered pig fat) is probably not a terrible option. It contains almost no water or sugar, so doesn't grow mold, and the grease prevents the tissue from drying out. Still, Caretaker will probably want to soak that bandage before they remove it.

The bandage should be clean linen. Not wool. If Caretaker has to rip up their clothes for bandages, at least use the undergarment, and the parts of it that are less dirty (sleeves).

A cavernous wound (ie from a drained abscess) might need to be tamponaded, that is, lined with a strip of wet cloth, to keep it open and help with drainage.

Various herbs, honey, spices, etc, have historically all been used to promote healing, some more successfully than others. However, everything is potentially contaminated with germs and fungal spores. Putting mashed plant matter that hasn't been otherwise treated into wounds is always a gamble.

Disinfection is a possibility, but an effective disinfectant will also damage healthy tissue. If Character has their wound bathed with wine or spirits every time the bandage is changed, that wound will become necrotic.

Stitches are likewise a double-edged sword. Pulling the edges of a deep wound together will make it heal quicker and more smoothly, but it also retains exudate in a warm, anaerobic environment, which makes an ideal growing environment for nasty bacteria. Balance risk and reward appropriately.

Some additional thoughts:

Medicine has taken unimaginable leaps during the last ~150 years. Things that would have been a death sentence to our ancestors are barely more than a nuisance to us. As a result, we have a fundamentally different attitude towards treatments, especially invasive treatments. We do surgeries as precaution or to restore optimal function, where in the past, surgery was often a last resort. It was very risky, and ran a good chance of killing the patient, so it would only be done if they would die anyway.

That doesn't mean doctors and surgeons of the past were helpless, there are a lot of amazing and very sophisticated treatments, that are older than you'd think. For as long as we have been human we have tried to heal each other, and were often successful.

Just because we know humoral pathology is wrong doesn't mean it's stupid. It's based on very solid observations of health and the human body. It was the accepted theory for a long time. It makes no sense for a doctor in that setting to reject it.

The human body is at once more resilient and more fragile than most people think. Humans can walk off devastating injuries, a lot of things will sort themselves out. However, once a tipping point is reached and the body can no longer compensate for whatever is going wrong, there's no turning that process around. This is why systemic infections are so dangerous: Bacteria/toxins overwhelm the immune system, everything is poisoned, multiple organ failure, death. It's very difficult to come back from that, even today.