Yes, you can heat the soap after it has saponified to help overcome a partial gel. I am not sure you will completely lose the ring created by partial gel, but it will be more muted and the not-gelled parts will become firm and waxy as if the soap had fully gelled.
Preheat your oven to 150-170 F (65-70 C).
Put the soap back in its mold -- it makes no difference if the soap has been cut or not. If the mold you used is not safe to heat to those temps, you might need to put the soap on a parchment lined cookie sheet or some other heat-safe, fresh-soap-safe container.
Put the soap into the preheated oven. Let it warm for 1 hour or so, and then check the texture and visual appearance. If you do not think it's quite ready, let the soap warm another 1/2 hour or so. I don't see a lot of benefit from heating the soap a lot longer than that.
If you can spare the oven, turn the oven off at that point and leave the soap in the oven to cool down. Otherwise, take the soap out, cover it with a towel and let it cool slowly.
The soap will not look like it is in gel while it's in the oven. Cut bars will remain fine (at least in my experience) during this heating -- they don't "melt" or distort. I don't guarantee this if you use higher temps, but I have had good results when heating to 150-170 F.