As you can see mistakes happen. The fun part (and the challenge) is what you do about it.
In the first example is a commissioned piece that I painted called "You Are Beautiful". The first image shows you the start of the painting where all was well and then the finished piece. Unfortunately my paint brush does not have spell check and I didn't notice the mistake in spelling until the day I was to deliver the painting. There wasn't anything I could do except take it as it was since there was no time to fix it before or after work. What did I do? I told the client about it and offered to fix it. Funny thing is, they loved the mistake (for reasons I can't share here). I still have the offer outstanding to them for me to fix it. I would feel much better if they let me (smile).
The second painting is just something that came out of my head onto the canvas however, every time I looked at her, all I could see were those poor little puppies that are so inbred their eyes go in different directions. All I could do was either scrap it or fix it. I liked the direction she was going so I decided to fix her. I drew lines on her face for measuring to determine what the real issue was and it became very apparent. The left eye was about 3/4" higher than the right. I am sure this is due to the fact that I drew the face on an angle. So I painted out the eye to try again. And then I decided to just paint over the whole face and re-draw it in. I like her much better now but I still have some tweaking to do on that left eye. The outside corner needs to come down just a bit. :o)
I welcome the mistakes and find that they exercise my brain and lead me to new discoveries. They are little journeys that keep me engaged and my creative process infinitely interesting.