Unintentional Sour Oatmeal Stout

Anyone ever make a sour oatmeal stout with a lactose infection? How’d it end up? I took a sample and under a microscope it looks like lactos. What ever it is, I’m going to ride it out. It’s been in the secondary for nearly 3 weeks and the gravity is stable at 1.027. I put a brew belt on for a week and re-checked and still the same. Would it be a good idea to re-pitch? I washed the yeast (US-05) from the primary just to learn how to do it. I have two pint jars and can make a starter and throw back in if you would think that would get it going again.

I never have.
You might want to leave it at 1.027 to balance the sourness.