What are some excuses for self harm scars on thigh?

I learned years ago that when people ask what happened, they already know. My scars are all over my thighs too. Self harm is fairly obvious and easy to point out. I’m not sure if they think that asking will open the door for people to open up or what, but it is always uncomfortable. So instead of going through the awkwardness, I just started telling people clearly unbelievable things about 98% of the time, like I was bitten by a shark or got into a fight with an alligator. Most of the time people will respond in disbelief since that clearly didn’t happen, but I just say “yep” and move on.