"worsened further" is correct and usable in written English.
It can be used when describing a situation that has become worse than it was before. For example, "The drought worsened further after two months of no rain."
By 2003, Zadroga's condition had worsened further.
The news heightened Alfredo's anxiety, which worsened further when his father filed a police report, raising the risk of retribution.
Iran and Afghanistan also have Baloch populations who would surely be affected if the situation in Balochistan worsened further.
The channel's predicament was worsened further in the weeks leading to the trio's arrest by the broadcast of AJE material on AJMM, the network's now-banned Egyptian offshoot.
But it nevertheless indicated that central bankers would consider lowering interest rates only if the economic outlook worsened further in the weeks and months ahead.
The airline, based in Montreal, reported a net loss of 270 million Canadian dollars in the first quarter, and its financial condition has worsened further since it sought protection from its creditors on April 1.
Mr. Cardoso's government is now warning that the situation may worsen further.
And, if the confrontation between Russia and the West worsens further, that may no longer be possible.
If the economy were to worsen further, the fears of people like Mr Marcus would surely spread.
"How would I be able to support my new children?" Economists often predict a so-called "revolution of the hungry", should conditions worsen further.
Especially if conditions worsen, further government actions may be deemed necessary to shelter banks, businesses and consumers from the financial turmoil.
