really bad razor burn

so i've never been really good at shaving my bikini area but i've been trying to work on it for the upcoming summer. I just shaved my bikini line with shaving cream, got a brand new pubic razor for the sole purpose of shaving, went in all the right directions, hot water after about ten minutes in the shower... and i have literally the worst razor burn I've ever gotten and it's SO PAINFUL. wtf am I doing wrong??