what u have is post inflammatory hyper pigmentation.
after wax u have reactive folliculitis
and it heal with dark spot.
dont rub or scratch over it
avoid using any cosmetic product over it
u need to take treatment from dermatologist
he will prescribe u some cream to remove spot and good moisturizer lotion
wear loose and cotton cloths
avoid frequent waxing
do test over small area before going for full waxing.