Salem

I've used about 15 leeches and still cant heal from the fever.
"Your head is throbbing, your body boiling" is obvious I have the fever, how come I cant heal after using 15 leeches?
(I have fewer in inventory due to KO)

It's possible that you don't have maroon fever. Each disease has a certain symptom that becomes more noticeable than the others as you get sicker. Seeing as your disease bar is over halfway full, one of the symptoms (dizziness, coughing, headache, vomiting) should be occurring much more than the others. Find out which disease you have based on the symptom and use the correct cure.

OMG the tooltip trolled me so hard then, assumed that was the symptoms. GG SALEM

Illness is one of the hardest mechanics Salem has. The more cures you try, the less of a chance they will work. If you pick the right cure for the right disease it starts at 90% chance of success I believe and goes down to 10% eventually. Here's how you cure any disease.

First, Count the symptoms. If you get 6 headaches out of 10 then you probably have that disease. The diseases symptom gets more prominent the sicker you get.

Second, use 10 of that diseases cures in a row or drink a full canteen of willow bark tea or leave the leech on for awhile until you are cured. Once you know the disease and have a good supply of the cures then you can cure anything easily.

If you don't have a grinder or antlers or a clay pot or a leech, just create a new character and play on that for awhile until you can cure your other character with the new character.