I had several external and some internal stitches in my quad when they removed some skin cancer. It hurt to run the first three days and it really pulled but by day four it felt good enough to run some. By day seven, no problem. I guess it depends where they are and how deep the injury. Give it an easy try and if it hurts stop. It’s only mid August and the race isn’t till Oct - you are worrying too much. Nominal fitness loss in a week. Rest might do you good.
As for swimming in the ocean, I think you should wait until you get the stitches out. Why risk it.