|Sounds like a tapering dose of Prednisone. In most cases that's what they give. Now a days you get a shot of Solumedrol and then a Medrol dose pack that tapers the dose down each day until you only take 4mg on the last day (usually only last for about a week). The body needs to be tapered off of steroids, otherwise some bad effects can happen. Steroids decrease the bodies inflammatory response and that decreases the swelling and allows your body to heal.
Sounds like you had a good response, but abnormal to become immune just by getting a steroid, though you had a lot of it (I envy you). There have been cases when people who had a bad reaction to medications like penicillin that, after several decades, were able to take the medication again. The body hadn't seen it in such a long time that the immune response was forgotten.