I have a sebacious cyst right now in the bend of my inner leg as well... right where the saddle rubs... I actually get ingrown hairs worse FROM shaving... so now I use a trimmer and wear board shorts (they look better than a swimsuit with my tan lines anyway)...

the cyst I have will not go away on it's own... it's been there for months now... it goes down and seems almost flat until I ride... then it puffs up, is painful and will sometimes burst and drain on my shorts during a ride. I have an excellent fit etc as well...

my doc said this will not go away on it's own. If it didn't hurt I'd leave it... but mine is being removed June 6... stitches adn 2 weeks off the bike