Green’s Dictionary of Slang

bung n.3

[SE bung up, to bruise, to beat]

(US) a lump, a swelling.

[US]J.H. Carleton Prairie Logbooks (1983) 14 Aug. 20: The fact of his having one eye slightly shadowed by a faint knuckular abrasion remotely resembling a bung.
[US] in DARE.