Looks more like a raw rash. Just wash it like mentioned. Nyala my brindle had that a yr ago and I always keep on had a bottle of coconut oil the fractionated one like 2oz n add 10 drops of each... lavender, tea tree, frankincense and 5 drops of cloves. All are anti inflammatory n clove is a powerful antibacterial.
My Frenchie gets little rashes from time to time as well on his belly or legs. What I do is I'll wipe him with a Duoxo wipe in the morning and then in the evening wipe the area down with diluted povidone iodine and then apply coconut oil. The rash will usually go away in a few days.
The best thing however will be to figure out what is causing the rash. It could be food related, contact allergy or environmental allergy or maybe even something totally different. What are you currently feeding?