How To Treat Severe Diaper Rashes Leading To Red Bumps In Genitals?

Hi my 2month old daughter is having severe diaper rash or something i don't know but it's all red spots on her butt , in the vagina nd around that area also there are big lumps of redness very bad in shape its been 20days now no improvement.i am using destin cream nd Johnson diaper rash powder but no improvement.please tell me what to do