[MeganJ]

Never had anything like that using progesterone cream and I have used almost every brand I can find. From my previous experience as a chewbacca body double, it just looks like a blocked hair follicle which has resulted in growth under the skin.  My money on the cause would be an in-growing hair.....I could be totally wrong but have had issues with ingrown hairs where they get very swollen and are difficult to get out.  Some hair removal methods are more pre-disposed towards in-grown hairs, but usually they are very easy to get out as the hair breaks the surface before going back in, however occasionally they dont break the surface of the skin and grow back in which makes them very difficult to remove and they can get very swolllen.  

I would doubt its an issue from the progesterone cream at all especially having such a one off reaction, if anything there would be a more general rash rather than one very pronounced swelling.  Might be worth asking your doctor if skin creams might cause such as reaction - I wouldnt specifically mention progesterone cream but if you just said you had applied skin cream the doctor would be able to rule that in or out as the cause - which I would expect they would rule out given the very localised reaction.