Saddle Sore or Pilonidal Abcess?
Do you remember if the Doc called it Saddle Sores or a Pilonidal Abcess?
Pilonidal Abcesses were documented back in the 1940's as "Jeep Disease" due to the fact that it was most commonly found in enlisted men who were riding across dirt roads in bouncing army jeeps all day. It is present, yet dormant, in about 1/5th of the population as a cyst at the base of the spine/tailbone (aka top of your crack), and only becomes infected or inflamed when aggrivated by constant pressure, a hard fall, or infections such as ingrown hairs or bacteria from unwashed cycling shorts.
If this is what the Doc said, try using Tea Tree Oil. I know it sounds like hippie-homeopathic-mojo, but the natural antibacterial and antiseptic characteristics of the tea tree oil will protect your sensitive undercarriage. It is readily available in some supermarkets and drugstores, usually in the vitamin or organic section of the store. It's small, easy to apply, and it smells great too. Quick fix, preventative measure, pleasant scent!