I never realized how serious a saddle sore could be until I got this story from a nurse I was riding with this year:

She was on a century with some other women, and around the 80-mile point,
one of them began complaining mightily about saddle soreness.
The rest of them kept telling her to HTFU, and they all finished the ride.
The woman wound up in the hospital with intravenous antibiotics for the infection from the sore.