I didn't read through all the responses, but I've found that when I'm done riding and my horse has been squirted off, I comb his mane over and lay a towel over his neck and tuck the edges under his halter and let him stand to dry. It's worked wonders for some very mishapped looking horsies!
The key is to consistency, with whatever method you choose..... it won't fix itself in one shot. Sadly, it's an ongoing battle for some!!
Gallop as if you'll die tomorrow, jump as if you'll live forever.