Jesy Nelson once took tablets that were so powerful they made her vomit.
The singer, 29, who recently announced she's leaving Little Mix, had to take antibiotics to treat a painful tooth infection.
She took the strong pills so she could continue to perform with the band at a 2014 concert.
The quote has resurfaced as Jesy explained her decision to quit Little Mix, saying her time in the pop group had taken its toll on her health.
Writing in Little Mix's autobiography, Jesy also revealed that she was once so stressed with fear about her mum's serious heart condition that an infected ear started to bleed.
She said: "The pain got so bad I was in bed screaming.
"What's weird in this job is that people don't seem to believe we get ill like everyone else does – or that the people close to us get ill and we need to be with them."
A year later Jesy had 50 injections of painkillers so she could perform with Little Mix on America's Got Talent.
She said she was expected never to take time off to rest or recover from illness.
Jesy wrote: "On the day, my shoulder went and I couldn't move.
"In the end I had something like 50 injections and my back was smothered in bruises.
"Before the show, when I was getting my hair and make-up done, people were feeding me coffee to wake me up.
"I was so out of it I can't remember anything much about the performance, just that on stage I couldn't get my balance. It was awful, the worst thing I've had to do.
"In a normal job you can take a day off and no one has a go at you, whereas in this job if you miss a performance, everyone's writing articles, commenting on social media and throwing abuse."
