It means to endure a difficult period of time or situation with a strength of will.
It can be a good idiom to use in place of words like, “endure”.
To help you, below are some examples of using this idiom.
“If I had to move for my job, I would bite the bullet and hope that it turned out for the better.”
“Sometimes you just have to bite the bullet and get the job done!”
Here is a video conversation with my friend and writer, Eric Drysdale. We catch up after a very long time (we went to high school together). We talk about the difficulty making a decision to move to another city for a job.