My guess is that you are overdrawing a bit. From the location of the mark, you are pulling the string too far back and it is riding along your cheek and to the side of your eye. You may also be laying your head over a little to "snuggle" up to the string and that will make the "scrape" worse.
This is fairly common for C bow shooters initially due to the "slightly" different mechanics of drawing a C bow and where the release hand is located at full draw.
As others have said, we really need to see pictures of you at full draw AND/OR a video would be BEST so we could see your entire shot.
Arne