Singulair and jerky movements

My son, who is 3 years old and 8 months old has been taking singulair for more than a month now and we noticed that he started having some kind of tic disorder. it started with eye widening and blinking then lately he had several unusual jerky movements of the neck and upper extremities. We do not know if this is a type of Hyperkinesia (exaggerated muscular movements) which is one of the side effects written in the manufacturer's drug information sheet. We are very concerned if we should start discontinuing the medication.