For new painters it can be very hard to have a painting that you have been working on for weeks and months to be destroyed by one silly mistake.some of the artists may leave the canvas alone and decide to start the painting afresh others may be inspired to move on amidst the mistake and there those who can turn the mistake into something artistic.
A watercolor mistake can be rectified using water spray.The idea of using the water spray may sound insane, but it works you can do it and protect the rest of the painting using masking tape.
You may also want to use a pestle if you're not comfortable with the water spray the pestle is mostly used to cover huge areas that have been overworked, and they make the areas appear as if they were freshly done and no much work was done on the part of the painting.
Having an art block is normal for every one the difference is how you are going to overcome the block and how you are going to be inspired to be able to start painting again.
When you get an art block, and you can't be able to paint the first thing is to take it positively by doing this you can be able to come up with new ways and come out of your cocoon of art blockage.
The other best way to overcome artist block is to go to a community art center or even go to a local art school this implies even to the professionals who are also doing as a career this is for art inspiration.
The other thing you can do is call your friends to go to an event like hiking and come up with sketches that inspire you during the journey or even try sketching your surrounding this will help you get rid of the art block.
Having a critique for your work is very important a critic helps you overcome your challenges and helps you become better ,you can invite a fellow artist to come and see your work in order for him to critique and help you overcome your block.
Art exhibitions are also places where artist go to get there block removed this is easily done by seeing what other artists are drawing and being inspired by this helps you get into the mood of drawing you can also talk to the artist and he can give you new ideas.
Boredom is one of the reasons why many artists may get art block you can overcome this by going to events or even getting out of the studio for once this can help a lot and when you come back to the studio you may have fresh ideas for a canvas.