What exactly are you calling a mistake? You might need to adjust your perception of a mistake.

Like the GT admin said, don't beat yourself up about it. One of the most important skills IMO that you can learn is playing through mistakes. What you think is a mistake your audience may not even notice. And so what if they do...play through it and move on.

Don't make the "mistake" (see what I did there :) of focusing too much on perfection. You don't want to become complacent, but don't let mistakes cause you stress or overshadow the progress that you are making.

I play in a duo and get out about twice a month to play. Honestly, it's the rare song that I don't make a few mistakes. I may miss hitting a note. I may play a bend that was a bit flat. I may be off in my timing. I've even started soloing in the wrong key! (That one I try not to make a habit!) I may hit the wrong chord. If we get through a song perfectly, it's cause for celebration :). However, most of the mistakes are things that nobody in the audience would notice. The reason why most people don't notice is I've learned how to play through the mistakes. When you are in front of people, there is no stopping and starting again so you can get it right...the train keeps rolling!

When we watch lessons here, we see perfection, so we expect to be perfect ourselves. I would bet money that there are plenty of outtakes where Mike O., Anders, Andy, or any of the instructors have gone off the rails playing something for a lesson. Some of that would be interesting to see I think...to show that even these monster players on this site are human and do make the occasional mistake.