If the scratch is small enough, sometimes you can get away with using a little wax on the dvd. Spray Pledge works sometimes, other people use carnuba wax.
If that doesn’t work, you can try to buff out the scratch with very fine abrasive. Toothpaste sometimes will do the job. Make sure to rub from out to in, not round and round the disk!!
I have also used an ultra glaze final buffing wax on occasion to rub out scratches. The brand I use is Meguiar Showcar Glaze #7.
Oh and forgot to mention, you can set up Decrypter to ignore read errors and hope you get through that section where the damage is without skipping too much, but don’t get your hopes up.