to make matters worse; what's worse
Fixed expression used to introduce an additional negative point, often at the beginning of a sentence.
I lost my wallet. To make matters worse, my phone battery was dead.
It started raining. What's worse, I didn't have an umbrella.
Standard mixed kanji-kana spelling.
Kanji form for さらに; less common in everyday writing.
Kanji form for こと; slightly more formal or literary.
Full kanji form; rare and formal.
Phrase composed of さらに (furthermore) + 困った (troublesome, from 困る) + ことに (adverbial form of こと, 'thing'). Literally 'to a further troublesome thing'.