Problem with my character mesh's mouth

My created mesh’s mouth on the left side got stitched up by accident, and I want to fix it so I can continue. It looks like two or three tightly knotted pieces of vertices, edges, and faces all bundled up at once. I tried dissolving and deleting the pieces so I could replace them with a proper mesh piece so as to look more normal, but just make it worse. How do I achieve this?

It’s hard to understand what you mean. Could you post pics and blend file for others to see?

From my experience, modelling lips can be tricky since the rest of the face gets in the way.
In this case, you can try hiding vertices that are in the way.
Or maybe press alt+B and drag the selection to only show the part of Td e mesh you’re working on? (When you’re done, you can press alt+B again to show everything again)

Or some of the lip’s vertices get too close to each other. I’m not sure how to deal with this. Maybe zoom in a lot?

Or ctrl +g to add selected vertices to a vertex group? You can have one vertex group for upper lip, another group for lower lip.
Just be aware that extruding vertices from an existing vertex might add those new extruded vertices to the existing vertex group.

I hope that helps.