brandy snap, n.¹ — Green’s Dictionary of Slang

brandy snap n.¹

[its resemblance to SE brandy-snap, a very thin gingerbread biscuit]

(Aus.) a scab on one’s face.

1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 26: BRANDY-SNAP: slang: scab on the nose or face called by a fall or blow. The implication is that drink is the cause of the injury.
1943		Baker Popular Dict. Aus. Sl. (2nd edn).