I have used tetracycline off and on for the past two years for the same problem you are describing, but built up a tolerance to it quickly and didn't have much luck. I was also put on Bactrim and it did help, but had to have blood tests done while on it which was rather inconvenient at times. Retin A and Renova and various other antibiotics have been tried with no luck, but I have had some luck with the Cetaphil and no water I saw posted on the board previously. The injections you decribed are also common, it helps to give you immediate relief from a large annoying cyst, you may find you needd multiple injections to keep it at bay if it persistantly returns. Best of luck to you.