From an unused root probably meaning to burn; inflammation, i.e. An ulcer; --boil, botch.
H7822. shechin
שְׁחִין noun masculine boil, collective eruption; — on man 2 Kings 20:7 = Isaiah 38:21, ׳שׁ רָ֑ע Deuteronomy 28:35; Job 2:7; possibly leprous Leviticus 13:18-19, 20, הַשּׁ ׳צָרֶ֫בֶת 13:23 (see ׳צ; all P), in Egypt, on man and beast Exodus 9:9-10, 11 (twice in verse) (all P), construct מִצְרַיִם שְׁחִין Deuteronomy 28:27.
שׁחף (√ of שַׁחֶפֶת and possibly of שַׁחַף; Arabic is pare, peel off; also affect with consumption of lungs; consumption, so Jewish-Aramaic שַׁחַפְתָּא [for שַׁחֶפֶת]).