Tear in my seat cover. What can I do?

that stich will tear the vinyl back out in one use, you would be called a hack trimmer and never have any repeat customers if you did that.
Not everyone is carrying a $1500 dollar industrial upholstery sewing machine that they can just whip out of their van to fix a seat for a fellow member.

The OP is looking for cost effective solutions that he can do himself.

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