Or will I just take my slip to the grave?
Macklemore is considering not telling anyone about his relapse to save himself from the shame of others being disappointed, or in reference to the previous line — so that people won’t consider him phony and continue to see him as real/honest.
Ben knows his words are powerful and many people idolize and follow him. To save the lives of many, he considers keeping his relapse secret to reassure those who follow him that it is possible to keep clean. In addition, he initially believes that his slip is not considered a relapse, as it is so minor, but a slip is a slip, and not something to be ashamed of.
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