One great thing about having less spasticity is that since you're not fighting against the muscle, you have less fatigue.
I was *thrilled* to have relief of the spasticity in my tongue. I could actually move it around my mouth and teeth without spasms. Yes, it is possible!
But yes, you have a weak muscle under there when it's not masked by stiffness and spasms! And it is really hard to build up that muscle without overdoing it. I found myself just shaking and trembling with weakness really easily.
So I hear everyone saying that the thing to do is to try a swimming pool because it's supposed to be much easier to "work out" in water. I still haven't found a pool, but maybe you can look for one, plus a PT who can help.