Period ... Prom ... White dress!?!

Jess 🦄
Does anyone have any tips or advice on what I can do!?!? 
My period is suppose to start the day of prom 😤 I have a thin white dress so can't wear large knickers or anything, so I'm going to wear a thong, anyone have any advice!?! 
Should I put a tampon in just before I leave just in case 🤔 
What if I leak on my dress 😱