This type of skin rash can be caused by many problems,mainly fungal infection.We need to check other areas as well for same rashes plus some details like whether it is itchy and since how long is this persistent and how often do you get it.All these details plus proper examination will help in making correct diagnosis. Once diagnosis is made we can suggest proper treatment and usually this clears completely without leaving any marks.
Next Steps
I would advice you to either provide all the details I have mentioned and send the pics if other areas are affected as well.Once you send all details I can suggest you some medicines.Also mention if you are allergic to any medicines or if you are already taking any medicines.
Health Tips
Do not scratch as scratching will make it worse and leave permanent marks.Dont use any random creams as steroids creams may worsen this later.