Oh hun, I know how you feel - I'm a chronic chafer and I'm already getting it because the weather's warmed up so much.
My best advice - go knickerless as much as humanly possible and make baby powder/cornstarch your new best friend. I found creams etc made it worse for me, baby powder/Curash was the best treatment for me personally.
If you're not into wearing shorts but want to go commando, try wearing long, loose skirts (eg peasant/gypsy-style) so you don't have to worry about them hiking up or a breeze catching them

Good luck, I know you're probably already feeling uncomfy enough without the added pain of raw skin in the bikini area Hope you can get rid of it soon!