Jamieson, Fausset and Brown on Job 16:8

8. filled ... with wrinkles--Rather (as also the same Hebrew word in Job 22:16; English Version, "cut down"), "thou hast fettered me, thy witness" (besides cutting off my "band of witnesses," Job 16:7), that is, hast disabled me by pains from properly attesting my innocence. But another "witness" arises against him, namely, his "leanness" or wretched state of body, construed by his friends into a proof of his guilt. The radical meaning of the Hebrew is "to draw together," whence flow the double meaning "to bind" or "fetter," and in Syriac, "to wrinkle."

leanness--meaning also "lie"; implying it was a "false witness."