Settled down privately for a small damage

[joeforl728]

Hello, I am in Ontario, Canada
I was in bad luck today so I hit somebody's car in a parking lot. I did not run away, instead I looked for the owner. I found him and he understood my background so we decided to deal with this privately.

We went to two body shop to make a quote on the damage of his car. Two different body shop, one is like a dealership-certified and the other one is more like private business, have almost estimated the same price: one is 638 after 100 discount and the other is 600 (cash payment).

In terms of money, I definitely went for $600 and the other party agreed on this. So we went to the bank and I got her a money order with a receipt held by me now.
It seems everything has been settled.

But I am still worrying if she later finds out and even prove (says, she is not a lair) there is another dent on the side door due to this accident and she asked for more money, says 100 or 200 more, because it is needed to repair for that part, on top of the $600 we agreed earlier.

So I am wondering, in laws or insurance rules, whether she would even have this option to ask for another 100 or 200 from me. Or whether she would have an option to report to her insurance company if I refused to pay for the extra.

Techically she could yes...Best to get it all in writing that the fee you agreed is for final settlement of the issue. Then she cannot come back for more.