What is Diaper Rash?

It’s when your baby’s skin is irritated in the diapering area. This rash could be any shade from pale pink to a bright red and sometimes may have little pimple like spots. It is usually on the lower abdomen, genitals, around the anus, and in the folds of skin in the groin. The buttocks are less often involved. Most babies get diaper rash some time in the first year of life, especially around 9 months to a year.
What causes diaper rash?
Many things can irritate your baby’s skin when it has prolonged contact with the skin. Pee and poop are both irritating and can cause a rash when a diaper is left on too long. Sometimes a baby may be sensitive to the diapers being used and you may have to change brands. If you use plastic pants over cloth diapers these may irritate your baby’s skin. Lotions, and powders can also cause a rash. Diaper rash is less common in breastfed infants and more often seen when your baby starts to eat solid food or if your baby should have diarrhea.
How should you treat diaper rash?

Treating regular diaper rash is easy; just eliminate the irritants to the skiin. Change your baby’s diaper frequently and clean your baby thoroughly each time with a soft cloth, plain water, and a mild soap (after a poop, not after each wet diaper). The more you keep your baby’s skin dry, the more likely the rash will go away. So let your baby play without a diaper on when ever you can, place a waterproof pad or towel under your baby incase of accidents. Try not to use any lotions or powders on your baby’s skin, but do use a good diaper rash cream each time you put a clean diaper on, such as Aquaphor or A&D ointment. If after two days of more frequent diaper changes and skin cleansing the rash is still present, try zinc oxide (a common ingredient in over-the-counter diaper rash creams) or A&D ointment® to protect the skin.
If the rash does not improve within three days, is spreading, or develops blisters or pustules (pus-filled, raised blisters), you should contact your child’s physician.

If you baby has little pimple like spots in the diapering area, then this is probably a yeast infection. I would contact your child’s physician to get the appropriate care needed to deal with this.