Never overpack a bag. It will stretch and permanently distort the leather. Anything too big can leave a press mark, especially in a soft leather. This is what you're seeing here.
Never EVER put a cat in a Hermès bag !!1!!!jb!!!

I would try storing flat in a light cotton Pillowcase or dust bag for a day or two , it might just reshape overnight ..
If it doesn’t , you can find something to put inside it that hugs the natural shape of the bag and you can then put an object such as a small heavy bible on top to flatten the leather .
Short term use only though , or you could end up with a reverse stamp !!!!
When I moved over here from uk a couple of leather steering wheels shifted in shipping and left dents in the leather .
The newer one fixed itself in a day or 3 , the harder vintage one took a couple of weeks cushioned on towels in a hot garage whilst manipulating the small dents with leather cleaner/conditioner every day or so ...
Yours is newer , and bigger .
So should be an easy fix if it doesn’t fix itself .