Would you consider buying several coordinating tiles that you can form into a design element. Sand burned area. Glue tiles in your design over the burn. Let dry. Make sure you glue the entire tile surface so water, etc, won’t go under it. 😊
You can buy some countertop paint and paint the entire countertop.
There are many laminate fillers on the market. You could use one of them to fill the hole. Depending on what your countertop looks like it might even blend in. Follow the directions that come with the product you choose. If you can't match it then you could look into painting your countertop. There are several ways to do that so it depends on what look you'd like and your skills for the sealer. I hope that helps. Wishing you the best.