Lewis structures are fundamental to learning chemistry, yet many students struggle to develop a complex understanding of its meaning and uses. Writing-to-Learn supports students in developing a deeper conceptual understanding of the topic, making it an ideal pedagogy to apply to student learning of Lewis structures. One difficulty often associated with classroom writing is the capacity of instructors to provide feedback to each student on their written work; however, this practical constraint can be mitigated through incorporating peer review. Peer review and revision are known to support conceptual learning and yet are underutilized in STEM (Science, Technology, Engineering, and Math) classrooms. Additionally, peer review is an authentic, common, and necessary practice in chemistry research, which warrants its incorporation early on in chemistry courses. A major concern regarding the use of peer review-based feedback is the ability of students to provide concept-based feedback that is both correct and detailed enough to enhance student understanding and support substantial revisions. In response, this work investigates the relationship between revision and the characteristics of students' peer review comments in the context of a Writing-to-Learn assignment focusing on student understanding of Lewis structures. Chemistry students wrote a summary of Lewis' 1916 paper introducing Lewis structures, participated in peer review, and revised their work in response to a structured prompt detailing specific chemistry concepts to be covered. The peer review comments and students' revisions were thematically analyzed. The peer review comments were deductively analyzed according to an analytical framework to characterize the usefulness of comments. The extent and type of student revisions were also analyzed and paired, if relevant, with the associated peer review comments. Results indicate that students provided both detailed and conceptually focused comments on their peers' work, irrespective of specific chemistry content being addressed. Although the assignment and peer review rubric were content focused, students made a mixture of editing and content revisions following peer review. These results suggest that further scaffolding of what constitutes good feedback and revision may further promote student learning.