I have sewed sackcloth— The meaning of this verse is, I have sewn sackcloth (in token of grief) over my torn skin, and have defiled my head, my horn, or honour, with ashes. See Schultens and Heath.
Related Commentaries of Job 16:15
Job 16:15
15 I have sewed sackcloth upon my skin, and defiled my horn in the dust.