IPhone back screen cracked!?

So I dropped my phone, and it fell, and cracked the back screen >.< I have the otter box defender so for right now, it covers the cracks except for the apple symbol D: I'm only 14, so I'm sure my dad will MURDER me. I'm scared to tell him the truth, do you have any really good excuse I could use? Like I dropped it at school or something? Or any way I can fix it? D: Thanks