Synonyms for Work up:

n.

fear, agonize, panic, worry, dread, hardly dare (to) breathe, have a lot on your mind, upset yourself, fret. experience, enhance, possess, burn, improve, walk away with, nurse, feel, let yourself go, tingle, overflow, refine, give up to. create, bring about, inaugurate, invent, catalyze, start-off, trigger, set off, form. work up (noun)
build up, work out, build, progress.

v.

agitate (verb)
worry.
cause (verb)
create.
change (verb)
build up, progress, build.
energize (verb)
build up, trigger.
engender (verb)
bring about.
work up (verb)
improve.

Other synonyms:

trigger. energize
trigger.
Other relevant words:
create, invent, fret, trigger, improve.