A death mask keeps a face exactly as it was at the end, so tradition reads it as a frozen image of someone — or of yourself — that no longer changes. It speaks of memory and of a likeness held too still.
When this appeared in your dream, what were you feeling?
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.