There have been times when I have experienced a fair amount of pain with playing with the left tongue and the last few days have been tough. However the pain seems to becoming more on the right side jaw by the TMJ joint down through the angle of the jaw and along the lower border. After the pain becomes pretty intense it is hard to feel exactly where it originates. I have taken advil and tylenol more than once and have been unable to sleep at times.
I think the way I used my jaw musculature favored the right tongue jaw in a slightly lengthened position as compared to the left to allow for greater range of action with speech and communication. As my left tongue/jaw musculature seems to grabbing more space my right side is trying to accommodate the new position somewhat unsuccessfully at this time. The left side movements though powerful are spastic and not well controlled. There are times when the pain disappears and comes back when I start playing with the left side control and movements.
So obviously a person with at least a shred of sense would stop trying what I am doing. I don't see any particular benefit in trying to develop the left tongue but it does suggest to me that the right left division in terms of handedness is false. I am right handed based on the way I perceived others and habits of use but could be left handed. (Left tongue/head/spine dominance leading to left shoulder arm hand control and dominance.)