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 for difficulty breathing, swelling of the face or throat, collapse, or widespread hives with dizziness.
These can be signs of a severe allergic reaction.
Seek urgent medical advice for a high or persistent fever, a widespread blistering rash, marked weakness, confusion, or rapidly worsening illness.
Contact your healthcare team during routine hours if redness or pain is worsening rather than improving, if side effects interfere with normal activities, or if you develop a chickenpox-like rash.
Also call if you learn after vaccination that you were pregnant or had an immune condition or medicine that was not discussed beforehand.
Every sign above is quoted from the sofidex article on varicella-zoster virus vaccine live (Oka-Merck) strain. If you are not sure, err upward — it is always reasonable to be checked.