I would guess it is masking the symptoms if they come back that quickly when you stop it, a matter of three days! In my case, however, I will get more neuro symptoms within two or three days if I get off the Swank low fat diet, that is, if I eat red meat two days in a row (as when traveling, unable to get own food). I begin to stagger, meander, etc. I would say in your case, however, that enduring the symptoms is better than what you had on the drug. Perhaps you can take some things to mitigate the symptoms. I take Zyrtec (antihistimine) for itch. I don't know if your reason for having itch is similar to mine...mine comes primarily from another disease, Polycythemia Vera. But Zyrtec might help?
My jerks and spasms were back last night, in spite of taking enough magnesium. I attribute it primarily to the smoke pervading my environment from the New Mexico forest fires. I am very sensitive to smoke. Sometimes it is just impossible to avoid symptoms.