My lip was split all the way through and I got stitches, everything else is healing except a small flap?

It is hard to tell since only some of it was stitched (why they did that was stupid). It will heal eventually, but it could take many years, or it could take couple months--it all depends on your body chemistry. The fact that it isn't swollen and doesn't have an infection is really good! All I can say is don't stress that area in your mouth (if you can help it). Hope it heals fast!