הִבְאִ֣ישׁוּ נָ֭מַקּוּ חַבּוּרֹתָ֑י מִ֝פְּנֵ֗י אִוַּלְתִּֽי׃
Zaropiały i zajątrzyły się rany moje, dla głupoty mojéj.
Rashbam
ימקו from the word נמקו חבורותי, “my wounds stink and fester.” The construction is similar to יסעו and יסעו (yissu and yissa-u)
Rashi
ימקו — This is an expression denoting “melting away” and therefore means the same as ימסו, “they shall melt away”. Similar to it are (Zechariah 14:12) “[their eyes] shall melt away (תמקנה) in their holes”; (Psalms 38:6) “My wounds נמקו, melt” (i. e. run with pus).