Purpose The aim of this pretest–posttest study was to investigate the reach and effects of My Changed Body (MyCB), an expressive writing activity based on self-compassion, among head and neck cancer (HNC) survivors. Methods This pilot study had a pretest–posttest design. HNC survivors received an invitation to complete a baseline survey on body image-related distress. At the end of the survey, HNC survivors were asked if they were interested in the intervention study. This entailed the writing activity and a survey 1 week and 1 month post-intervention. The reach was calculated by dividing the number of participants in the intervention study, by the number of (1) eligible HNC survivors and (2) those who filled in the baseline survey. Linear mixed models were used to analyze the effect on body image-related distress. Logistic regression analysis was used to investigate factors associated with the reach and reduced body image-related distress. MyCB was evaluated using study-specific questions. Results The reach of MyCB was 15–33% (depending on reference group) and was associated with lower education level, more social eating problems, and fewer wound healing problems. Among the 87 participants, 9 (10%) showed a clinically relevant improvement in body image-related distress. No significant effect on body image-related distress was found. Self-compassion improved significantly during follow-up until 1 month post-intervention (p=0.003). Users rated satisfaction with MyCB as 7.2/10. Conclusion MyCB does not significantly improve body image-related distress, but is likely to increase self-compassion, which sustains for at least 1 month.