Soot is what fire leaves behind, so it stands for traces of past anger, conflict or hard work that still cling. Being covered in it can reflect feeling marked by an experience.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.