1) Aggravate 2) Cheapen 3) Deteriorate 4) Exacerbate 5) Inflame 6) Intensify 7) Irritated 8) Rankle 9) Retrogress 1) Become more severe 2) Change state 3) Decline 4) Deteriorate 5) Exacerbate 6) Go downhill 7) Go downhill, so to speak 8) Grow worse 9) Head south, so to speak 10) Make worse 11) Start to go to pot 12) Take a bad turn 13) To become worse 14) To get the better of 15) To get worse 16) To impair 17) To make worse 
• (v. t.) To make worse; to deteriorate; to impair. • (v. i.) To grow or become worse. • (v. t.) To get the better of; to worst.
Wors'en intransitive verb To grow or become worse. De Quincey. « Indifferent health, which seemed rather to worsen than improve.» Carlyle. Wors'en transitive verb 1. To make worse; to deteriorate; to impair. « It is apparent that, in the particular point of which we have been conversing, their condition is greatly worsened .» Southey. 2. To get the better of; to worst. [ R.] 
[v] - make worse 2. [v] - grow worse
exacerbate verb make worse; `This drug aggravates the pain`