(Girls) What kind of razor should I use?

I have to shave the opposite way that my hair grows because my hair is so thick that that's the only way I can remove it. But lately, I've been getting so many ingrown hair, everywhere! I am thinking maybe it is my razor blade? I have always shaved this way, so why is it doing it now? Could it be due to not cleaning the blade thoroughly in the past? What kind of blade will prevent razor bumps? Thank you. :)