Major mistakes, usually the irreversible kind, begin with an unwillingness to tell the truth or an unwillingness to hear it. You pay a price for telling the truth, but it costs less than the alternative. Because truth wins.
Not telling the truth is too inefficient and too costly. Whatever price you pay in the short-term for being honest, the price you pay in the long-term for hiding the truth is much, much more.
Do the work.