I have a open pore in the middle of my back. I have had it for a few years know.  It has a hard bump underneath it . My wife used to be able to reduce the size of the bump by squeazing a hard white substance out of it until recently.  out of the blue it became larger and more painful. Any ideas on what it may be...
Hi.it might be a recurrent sebaceous or gelatinous cyst. It is best if you consult with a general surgeon to have a look at it, as this might occur again if not properly removed.