horrid razor burn PLEASE HELP!

I have super sensitive skin and i have HORRID razor burn. it’s mostly on the back of my leg and my back of my ass like near the crack? i did shave a few days ago maybe like 5 days. please give me your tips and remedies PLEASE! Tell me how to avoid and get rid of it i’ve tried everything!!!!! i always use a good clean razor & sensitive skin shave gel. please lmk!!! HELP