Green’s Dictionary of Slang

(drugs) covered with sores and abscesses from the repeated use of unsterile needles.

1980		S. McConville ‘Prison Lang.’ in Michaels & Ricks (1980) 526: A person may be bugged – suffering from many abscesses caused by unclean injections.
2001		ONDCP Street Terms 4: Bugged — [...] to be covered with sores and abscesses from repeated use of unsterile needles.