Um, any other signs of swelling or infection (are there little pimple like pustules forming around any of them)?, increased redness, soreness, swelling etc means that you could have infected the area with a blunt or unclean razor. Or could be plain, albeit severe, irritation. Either way, if you can have a warm bath with something like tea-tree oil in it and soak the area for a while. Then moisturise with a good cream (not just a lotion). If you can then not aggrivate the regrowing hairs ... so try not to walk, sit,....... basically everything really except for lying on the couch face down with an arse covered in cream and no pants (and I'm typing this and still not believing that I'm typing this and why the hell haven't I stopped yet). Soak and repeat.
Perhaps next time try some wax strips or depilatory cream if you're not going for the laser hair removal.