Atrophic acne scars are flat, indented or with an inverted center scars that develop at the endpoint of the normal healing process for acne. Acne scarring that remains after acne resolves has a significant impact on health related quality of life, including reduced self-esteem and embarrassment/self consciousness. ELAPR002f provides an immediate space-occupying effect for filling in the scar tissue. The purpose of this study is to assess how safe and effective ELAPR002f injectable gel is on adult participants with atrophic acne scars. ELAPR002f injectable gel is an investigational device being developed for the treatment of facial atrophic acne scars. There are 2 cohorts in this study. In Cohort 1, all participants will receive ELAPR002f injectable gel. In Cohort 2, participants are placed in 1 of 2 groups, called treatment arms. Each group receives a different treatment. There is a 1 in 4 chance that participants will be assigned to the saline active control group. Around 395 adult participants with moderate to severe atrophic acne scarring on both cheeks will be screened in the study in approximately 25 sites in the United States. Participants will receive 3 treatments over 2 months of intradermal injections of either ELAPR002f injectable gel or saline active control and will be followed for up to an additional 12 months. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, blood tests, checking for side effects and completing questionnaires.