The condition with which you have been diagnosed, hemifacial spasm, constitutes a twitching of muscles supplied by the facial nerve on one side of the face. In a very small number of cases the spasm may also develop on the other side of the face. Sometimes there may be even be a trigger for the symptoms, including tiredness and stress, or even use of the facial muscles.
Hemifacial spasm is thought, more often than not, to be the result of compression of the facial nerve by a blood vessel; this may be picked up with MRI, though that would depend on the types of images taken and whether contrast was used or not.
With respect to the facial weakness you describe, it is possible for the affected muscles in this condition to be weaker than the unaffected ones on the other side. This is one possible explanation, though from your question I am unable to ascertain the severity or extent of your facial weakness.
As for the weakness in your limbs, again it is unclear from your question as to the pattern and severity. One of the side effects of baclofen is muscle weakness, and this is probably why your Neurologist decreased the dose you were taking. If there has been no improvement, you need to let the doctor know as they will need to examine you again and look at the problem afresh.
There are a number of medications that are used in the treatment of hemifacial spasm, and certainly baclofen and clonazepam (Rivotril) are amongst them. A treatment which has been very successful in addressing the symptoms of hemifacial spasm is Botulinium toxin. It is an option you may want to discuss with your Neurologist; not all Neurologists are trained in administering it, and your current doctor may refer you to someone with the relevant experience.