Green’s Dictionary of Slang

1. a drunkard.

1848		‘Ned Buntline’ Mysteries and Miseries of N.Y. I 116: ‘Swell-head.’ A bloated drunkard.
1860		Wilmington Jrnl (NC) 29 Mar. 5/3: A swell-head came [...] he had an empty bottle, and his noise was like a cancer.

2. (US black) one who has passed out through drug use.

1983

R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].

3. see bustskull under bust v.¹