I have red rashes, what can it be?

Hello, I’m writing about red rashes along one side of my butt and scrotum that I’ve had for around a week. They are painful but not severe and itchy but not as bad as a mosquito bite. You can get a better idea by looking at the photo attached. Also I’m celibate so know its not an STD, and no trauma, travel, or anything out of the ordinary has happened. Any idea whats going on? Also please respond to my email and keep confidential not posting online or to others. Thank you.

Age: 30
Medications: None