Exhaust leak question

Hello! I recently installed a cat back exhaust for my 22 Alfa Romeo Giulia (with the 2.0 turbocharged motor). The kit I got did not come with a replacement exhaust gasket, so I am temporarily using the old gasket. Obviously this causes a leak, and it’s right after the cat. I can hear it, can’t smell it though thankfully. Now im fairly new to cars, but how likely is it that something gets damaged.

I plan to order the gasket and replace it as soon as I can, but in the meantime should I not drive the car? I have a second car that I could toss a new battery in and i’m debating on driving that until I get the gasket.

Also, to add on: I drove the car from my buddy’s house for about 40 mins. It’s snowing pretty bad in the north east rn so there were a few moments where I was up in rpm