Something wrong with spay incision almost 1 month after!

I noticed this on Nyx the last couple days. Today I decided it was time to call the vet first thing. She has a blue stitch that pops in and out about an inch. The incision is also bleeding and has yellow discharge. What could be wrong? I know they are going to make me pay another exam fee and make me pay for surgery if its needed again. I wonder if he used non dissolving stitches internally by accident? She has NOT been licking

Should have used the wrong stitches just to make extra money

And that looks like it needs taken care of how is she doing?

Shes acting normally. Were taking her in tomorrow and I am not planning to pay a cent.