Water parameters? The first thing to fogure out is if this is secondary to some type of trauma or if this an inceftion. It is difficult to tell from the picture, does the effected area appear to be an ulcer (deeper hole) or more of a superficial surface issue?
Some people are like slinkies...they serve no real purpose yet can still bring a smile to your face when you push them down the stairs!:p
Have a great day! Brian