Recent studies have argued that tutor feedback is failing to support students' progression. The potential for peer feedback, i.e. feedback composed by peer assessors, to support learning has been under researched. The aim of this paper was to explore a case study of a peer assessor composing and receiving peer feedback. The paper reports a case study tracking a peer assessor through the process of grading and composing peer comments and her reactions to receiving peer feedback. The data consist of feedback comments, reflections and a series of interviews. It was found that while the process of composing feedback comments was viewed positively, receiving comments was, on the whole, viewed negatively. The author suggests helping students to become peer assessors is a long-term process; initial peer feedback should be withheld. As students develop expertise in the subject matter and in composing feedback, comments could be exchanged.