4 weeks post fistulotomy- new abscess?

Hello all, hoping someone has some experience with what I am going through and can share their thoughts. 

Here are the details:

I have had issues with a perianal abscess since 2012. Mostly just having my colon/rectal surgeon drain it. This past March, it finally connected into my anus and became a fistula. I had what I believed to be successful surgery 4 weeks ago via a fistulotomy. I had my 3 week post op check with my doctor and everything was going well. A little drainage, but that was to be expected.

Yesterday, I got a too fimiliar pain in an area that is adjacent to where my current open wound is. That hard lump under the skin, that is sensitive to touch/sitting. This was the feeling I would get prior to the abscess popping or needing to go get it drained. 

So here I am 4 weeks posts fistulotomy and I feel like it was a waste. Has anyone one else who had a fistulotomy experiences this? Success rates are supposed to be over 90%. 

I do plan to call my doc first thing Monday AM but figured someone on this forum may have had similar experiences. 

Thanks in advance!