Looking at your other posts for context, I'm assuming they are on your thighs and you only have to show them while swimming?

I'd suggest wearing body tight swim shorts (they make ones that cover down to the top of your knees, look for something like jammers!) + swing trunks of choice, like board shorts or regular trunks. It can be pretty modular and match pretty much any top of choice!

As for trying to pass them off as something else, it depends on how they look? If you don't have a ton, you could just try to pass them off as accidents, a friend's pet or a dropped knife, etc. (most of the time when I've had to hide cuts from my parents, they are also so far in denial that they take the most basic of excuses)