Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services if a tremor begins suddenly with signs that could indicate a stroke or another serious brain problem:
Emergency help is also appropriate if shaking follows a possible poisoning or overdose, or occurs with seizures, severe breathing difficulty, or severe alcohol or sedative withdrawal.
Seek same-day medical advice for a sudden new tremor without an obvious explanation, especially after starting or changing a medicine.
If you have diabetes and shaking may be due to low blood sugar, follow your personal treatment plan.
Get urgent help if symptoms do not improve promptly or you cannot safely eat or drink.
Book a routine appointment if the tremor persists, becomes more noticeable, or affects eating, drinking, writing, walking, work, or other activities.
You should also arrange an assessment if it occurs with stiffness, slower movement, balance problems, unexplained weight loss, or a racing heartbeat.
Every sign above is quoted from the sofidex article on Tremor. If you are not sure, err upward — it is always reasonable to be checked.