Hiya,
Sorry to hear of your current predicament. Healing fistulas aren't much fun are they??
I haven't experienced what you currently are, but totally sympathise with the level of pain you must be experiencing. Are pain killers helping?
Is the hard lump like another abscess formation?
I hope that the anti-biotics help sort things out for you. It's bad enough trying to deal with the fistula healing as well as it all getting infected too...
Hoping you get over your infection very soon .....
