I've had many cortisone shots. I have great luck with them. I rarely have a problem. Once in awhile I will get what you have, remnants of the cyst. If its not swollen I would leave it alone, eventually rest of the cyst will dissolve. I would not recommend another shot for a month or so because you don't want atrophy. I never had a cyst get worse from a shot. I actually never had a cyst recur either after a shot. Hopefully you will have same luck as me.
Thanks for your reply. I'm glad to hear that. Would you recommend gently applying ice to keep inflammation away?