Where is it located precisely on the ear?

It's on or behind the tragus? My sister said that's what it is called.

No one knows exactly what causes acne but contrary to popular belief, spots like the ones that you describe are not caused by dirt. Most likely, your friend experienced a pimple. Pimpless form when hair follicles under your skin clog up. I'd suggest that if the skin of the ear still displays these types of symptoms that he go to see a dermatologist. Treatments include medicines and creams.