harm
damage
impairment
distortion
deformation
worsening
take a turn for the worse
misalter
deterioratingly
misreform
mischance
bad luck
mishap
aggravate
decrease
lessening
drop-off
deteriorationism
go backwards
worst-case scenario
disimprovement
disimprove
exacerbating
aggravating
exasperating
retrogressive
retrograde
kick someone when they are down
confound
crash
agudization
pejorate
go from bad to worse
beginning of the end
catastrophically
freefall
deteriorating
poison
have one foot on a banana peel
undo
degeneration
downhill
suffer
end of the world
hell to pay
run
bathos
anticlimax
chapter of accidents
changeableness