After the interim critique I followed the advice of my tutor and tried to use turpentine to remove the oil paint that the pen was shining through so that I could add more layers of primer. I soaked a cloth with turpentine and held it onto the paint as well as rubbing the surface of the paint. Although it made a difference, I found that not all of the paint was coming off so I used a butter knife to careful scrape off the remaining layers of paint. I managed to remove enough to be able to effectively prime the surface again. After priming another two layers I was able to paint over the pen with a few layers. Although it seemed to be a mistake to use permanent marker to trace my sketches, I think it was still useful as I could see it enough to not have to guess the composition of the image once I applied a little bit of paint. It was valuable that this problem arised because I’ll be able to use the pen to help in the future with the knowledge that a few layers of primer will not allow it to ruin the painting.