@Shalvenay It's Bluerot
While afflicted with Bluerot, a Victim grows grotesque blue boils on their face and back. This disease is carried by Undead (including the drowned ones in Tammeraut’s Fate), and victims most often acquire it through wounds caused by infected creatures.
The disease’s boils manifest in 1d4 hours, causing the victim’s Constitution and Charisma scores to decrease by 1d4 each, to a minimum of 3. This is quickly followed by a fever and tingling in the extremities. An infected creature is vulnerable to radiant damage and gains the ability to breathe Underwater.