>>>>If anybody can think of a method to get that result without leaving MOI Id be interested to know>>>>

I wanted to look at this for some learning. Although Michael has probably given a proper workflow, this is how I would fix it in MoI.

I projected curves onto the seperated tounge surface then ran a loft and joined it back in. It seems to have cleaned up that one area a bit, but maybe I have produced other pitfalls I dont see. Feedback welcome.

I did notice that trying to loft it, was creating some funcky stuff up at the tip of the tongue, where I was trying to end it with the little "arc". I tried a few different methods, and it would create a joined surface, but not sure if something here is problematic later down the road for something else???

Anyway, just focused with tunnel vision on the one little area and removed the crease from the join.