Hello, I sympathise with anyone who suffers from this; if heavy duty antibiotics can't reach the problem and have side-effects, may I suggest something more direct: try an old fashioned poultice like linseed and olive/castor oil mix.
Be brave! I have been trying this for the past week and a half and find it really has helped ease the aching. This was the traditional remedy for drawing out such problems, and I am hoping given time it will (dis)solve my problem.