Green’s Dictionary of Slang

hesher n.

also hesh
[? heavy metal + thrash]

(US campus) a fan of heavy metal music.

[US] P. Munro Sl. U.
Lisa Rose ‘Dated Vampires’, Little Buffy Site 🌐 There’s a goth one and a glam one / And a hesh one and a rockabilly.
[US]I. Fitzgerald Dirtbag, Massachusetts 95: [A] long dark room filled with hesher-looking barflies.