My 8 Year Old Son Has Had A Red Rashy

My 8 year old son has had a red rashy looking place on his side for about a week now, I have now noticed that there are now smaller red bumps that are around the same area and also on the opposite side of his body. the one place seems to have gotten a little larger. I at first thought it may had been a ring worm but it doesn't appear to be that.