It will ruin your integrity.
There is no such thing as an UNINTENTIONAL plagiarism.
NO. SUCH. THING.
If you are going to issue an apology... GET IT RIGHT the first time.
Do not go, "I'm sorry. It's my fault, but not really. I feel bad, it was a mistake. But not really. I'm super sorry."
"Oh let me try again, I'm sorry. But you see, I was confused and inspired. Therefore, it's kind of my fault. So I'm sorry."
Nope, not gonna work.
Resources For Bloggers (because this post is not completely useless):
"Walang sikretong hindi nabubunyag." - Old Filipino Saying (No secret can be hidden forever.)