Val,
that sounds like exactly what happened to me. I know it is sooooo disappointing. I had spent a year healing mine and had just a little tiny 2mm long patch that had not healed. I can't tell you how much I cried with my head in my husband's lap.
My advice--get surgery as soon as possible. No use letting it get bigger and more painful. Also, not to scare you but to reinforce the necessity of the surgery, if the abscess ruptures into your blood stream, you cold go spetic. They need to take care of this right away. My drs made me wait 2 mos and I got increasingly sicker and more pained each day.
A keyhole deformity is basically where one has a portion of the anal canal that will not quite seal shut. It is open and so makes the pucker look like a keyhole. The problem with this is that it may cause leakage and irritations. I have a bit of this. But it does not go up into the rectum, so it has not caused me any problems, aside from one. I did get soemthing stuck there the other week. That was painful and something to keep in mind, but otherwise no problem.