Very few people who have tongue splitting change their minds. Nevertheless, there are a few situations in which understanding the option of reversal is important:
Fortunately, reversal of the split is not very difficult. It can be performed under local anesthesia as an out-patient procedure. It involves removing (cutting out) the lining that has healed along the inside of the split from the tip to the deepest part of the split. This is usually done with a knife (scalpel) rather than cautery, so bleeding is typically more than it is with a split. Then, after bleeding is stopped, the tongue is sewn to itself from left to right, both along the dorsal and ventral surfaces of the tongue. There is greater opportunity for asymmetry in this operation than there is with the original split, so you will want to have an experienced surgeon perform this. Recovery is very similar to that of the original split.
The entire procedure is not unlike repairing a split earlobe. Speaking of which, it is also possible to repair earlobes that have been gauged, but in this case, the gauged lobes are repaired like a cinnamon bun rather than a split.