What does it even matter? I'm here and okay, right?!

[ but he knows dad in't going to let it go unless he says something... so thankfully an idea finally comes to mind ]

But fine! I got caught in a sudden current and it slammed me into some jagged rocks! That's why I'm late-- my tail was stuck!

Are you happy now that I've told you and embarrassed myself?!

[ it's not a complete lie, a current was involved and he DID get stuck but... well those cuts are pretty clean for "jagged rocks" ]