When should I re-dye Manic Panic?

I use Manic Panic Ultra Violet for my bangs and Hot Hot Pink for the bottom layer of my hair. The pink has already basically faded back to blonde but the purple is still pretty vibrant. I haven't done the pink in a little over a week and I redid the purple on Friday. I wash my hair daily. I was wondering when I should redye it so that it'll be vibrant for the weekend. I won't be able to dye it anytime after Friday, but the reason this is a difficult question is because im going to warped tour this weekend and I don't want the dye to run because of sweat or rain. Should I dye it soon, like today, and it just not be as bright but no chance of running or should I dye it later and risk the chance that it'll run?