HELP!! Going on vacation

I will be going on vacation for five days how do I keep my ball python Cossatot's tank humid for that long??

You could put some sparhgum moss in a "humid hide". Not sure how long it holds moisture without misting tho. That or maybe find someone you trust who is willing to come over and mist for you.

i can maintain normal 50-60% humidity just by having 2 water dishes with 1 over the heat pad (warm side). when i need to bump up the humidity for shed cycles i just wet the hand towel i have over the top and cover all but 2-3 inches of the screen. the hand towel definitely works better then aluminum foil IMHO. i only have to re-wet the towel about every 3 days & thats when its very soaked, but not actually dripping.
i'd say try it out before you go, if you want, just to see for yourself how it works. hopefully though you'll be able to find someone you trust to come over & mist for you or to come over and just check on the humidity but i strongly suggest putting a 2nd water dish in the tank & directly over the warm side if you dont already have one there.
now, my concern would be making sure your heat source doesnt malfunction in your absence...you got something to control that? something that is not likely to malfunction?
maybe whoever you have coming over to check on things should also check the temps to make sure everythings ok there.

Unfortunatly I have no one who will mist him so theoretically i only need the hmidity to stay good for 3 days caise I leave day one and come back day five

Place your water dish over heat tape/pad, add some damp spagnum moss or sea sponge. Everything should be fine.

Like everyone has said. And leave lots of water in there too. And even if the moss sponge towels whatever you use dries up in the 5 days, a few days of lower humidity shouldn't hurt unless hes in shed. Just make sure he can get a drink.