The Jennifer's Body actress announced that she will be removing her Marilyn Monroe arm tattoo in August, claiming that she just outgrew it.
One of Fox's close friends shared to Star: "After the first session Megan was freaking out over how badly it hurt. Her friend suggested a mouthguard to bite down on to help deal with the pain and protect her teeth.
"The mouthguard is working out nicely. It helps deal with what she considers absolute torture."
Fox revealed that the process of getting her tattoo removed is "a hundred times worse than the tattoo itself".
Fox can be seen in Sacha Baron Cohen's new political comedy The Dictator, to be released on May 11 in the US and on May 18 in the UK.
Watch the trailer for The Dictator below: