Quick answer
Blessing rests visibly on the righteous, while violence dominates the wicked mouth: either concealed behind it or returning to silence it. The Hebrew permits both readings, and both tell the truth about where violence finally lands.
Read both lines
The first line is a picture of blessing as something that settles visibly on a person, the way oil or a crown sits on a head. Blessing gathers around a righteous life; the community sees it and adds to it. The second line is compact enough that translators split over it, and the note below explains why. On either reading, the point lands the same way: violence hidden in a mouth, or violence returning to shut one, the wicked man's relationship with his own speech ends badly.
Why translations differ
The Hebrew of the second line can mean that violence eventually comes back and covers, stops, the wicked man's mouth, silencing him with what he dealt out; or, reading the verb the other way, that the mouth of the wicked conceals violence, hiding harm behind smooth words. Both are defensible, and the book repeats this exact line at 10:11, where the contrast with "a well of life" leans toward the concealment reading. There is no need to force the call: both readings are Proverbs through and through.
Related: Proverbs 10:11 · Proverbs 26:27
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.