revenge

i read genesis 4 today, and i didn't quite understand this particular passage:

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13 Cain said to the LORD , "My punishment is more than I can bear. 14 Today you are driving me from the land, and I will be hidden from your presence; I will be a restless wanderer on the earth, and whoever finds me will kill me."
15 But the LORD said to him, "Not so [5] ; if anyone kills Cain, he will suffer vengeance seven times over."

23 Lamech said to his wives,
"Adah and Zillah, listen to me;
wives of Lamech, hear my words.
I have killed [8] a man for wounding me,
a young man for injuring me.
24 If Cain is avenged seven times,
then Lamech seventy-seven times."
* emphasis mine

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i wonder if these passages mean that lamech was the one who killed cain.