Bee stings-swelling

Patient: I was stung by bees over a year ago. 3- bee stings in a two week period,..the last bee sting was in my calf and my entire lower leg swelled 3x its size. A dr prescribed a steroid and benedryl. The swelling went down but my calf and ankle are STILL swollen. It gets a little bigger by the end of the day. It is noticeable–a co-worker noticed just last week! Why is my calf and ankle still swolle?