I don't know what helps for razor burn, but I wish I did. I'm usually okay on my lower legs, but my thighs/bikini area get terrible razor burn that lasts for days, like what you described. I would simply recommend something other than shaving, like getting your legs waxed. You'll have to let the hair grow out for about 3 weeks, but the hair removed will be gone for a few weeks and you won't have razor burn. If you want to try the home waxing route, I've had the best experience with Sally Hansen's Sugar Wax kit; however, that may not be the best thing out there. Good luck.