I have a model that wasn’t built with actual loops around the mouth, but it looks like they are, but when you try to select them like a loop you only select a line, so I was wondering if there is a way to convert it into a loop, because you can use the knife tool to make a loop around it in almost the the same shape, so there has to be a way to make these into a loop.
Post the blend or at least screen shots.
um…I think you would have to rework the topology 
it’s often a pain, but it’s worth it if you can get it working correctly…
also, I’d suggest working on a copy of the file, just in case.
I’m no expert, btw, so there might be a way…i just don’t know how yet 
there’s also a trick to getting ring-like topology flow around areas like that…maybe you already know this, but say you have a certain shape, like a heart. if you wanted a continuous edge-loop around the internal edge ring, you could just select the ring and extrude it around, then join that to the rest of the mesh - it worked very well in my Tape Dispenser project