WEN (יַבֶּ֫לֶת, H3301). The KJV, ASV rendering in Leviticus 22:22 (RSV DISCHARGE). A wen is a benign skin tumor; but the Heb. text refers to an animal suppurating sore, perhaps a form of anthrax. Animals offered in sacrifice to Jehovah might not be defective in any way.
International Standard Bible Encyclopedia (1915)
Only in Le 22:22, "maimed" or "having a wen (margin "sores"), or scurvy," for (yabbal), "running," hence, "a suppurating sore" (compare the margin). A "wen" is a non-inflamed indolent tumor, and so "wen" is about as far as possible from the meaning of the Hebrew.