What Causes Reoccurring Pimple Like Rash On Inner Thigh?

I have reoccurring pimple like rash on my inner thigh.they happen about 3 to 4 times a year.about 2 or 4 bumps appear and disappear after a weak or there abouts.its always on my inner thigh so it gets extremely painful if urine drops on it.the first time I tried to bureau it.it produced water and was more painful.sometimes they look like ringworms when the rashes are clustered.

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