Just a follow-up. Since the cortisone injection, the sore has completely gone. It's still discolored, and that will likely take awhile to get back to normal, but there's no swelling, no tenderness, no cyst, nothing. I haven't ridden yet (even on the trainer) since I've been working late every night ($&#*%@ job), but I feel sure that riding would have been no problem even the day after the injection. I am so glad I had this done and won't hesitate to get an dermatologist appointment for another if I ever get a recalcitrant sore even during the riding season. It was one of the smartest and least difficult things I've ever done to cure a small but misery-inducing problem! 
Emily
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow