what would you do if..

Your sister in law lends you a night dress for you to go to a party.
Once you wore it you plan to return it...
you wash it since the fabric is easily washable and you iron it with a piece of cloth on top of it so you make sure you dont burn it. But the iron hits a piece of the fabric burning it .. as a result... you make a hole in a spot of the dress.
First you wat to kill yourself for being so careless for a second.
Secondly you get a panik attack.
Then you realize that the burnt spot is not impossible to be mend by a dressmaker...of course. So your plan is to take the dress to a dressmaker and try to solve the problem so if possible, it would never be noticed by you sister in law.
Suppose that the dress stays the same way as if nothing like this had ever happened... Would you tell your sister in law what has happened to you anyway and once the dress looks ok? ( she is very jelous of lending her things)
Do you think that she will remember exactly all the small details about the dress so as to suspect about anything? . ( Remember that one wears an elegant night dress not that frecuently , actually she wore it for first time three years ago)...
Or.. you would never say a word.... and let it be, see what happens?---
silly topic but awful situation...