Head shaking and neck tremor. Tr 40 mg?

Sir/madam, My mother is under treatment for cervical dystonia diagnosed an year back. At first she has taken nexito 5 mg tablet for about an year for anxiety and very less tremor sometimes. After an year she stopped tablet for 2-3 months and sleeplessness occurred then we consulted a doctor they gave petril beta 10mg but still the condition worsen neck pain and stiffness occurred, neck was going automatically to upward. Then she tried neck strech excercise and ended up with head shaking and full time tremor. Now doctor changed medicine to Nexito plus and Divalgress er 250 since 2 weeks and the condition improved alot with only left side minor neck pain and head shaking sometime while on bed head tremor. When we touch the neck left side muscle it has spasms. Since 5 days she has taken Betacap tr 40 and looks like the head shaking frequently and its heavier than before. Is it because of the new tablet? Can we stop the Betacap tr 40 mg?