Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency medical help if you have known or suspected high calcium and develop confusion, difficulty staying awake, repeated vomiting, severe weakness, collapse, or signs of marked dehydration such as very little urine.
These can be signs of severe hypercalcaemia.
After neck surgery, sudden neck swelling, difficulty breathing, or rapidly increasing tightness in the neck is an emergency.
Call emergency services.
Get prompt medical advice if you develop symptoms of a kidney stone, such as severe pain in the side or back, especially with fever, vomiting, or difficulty passing urine.
New tingling around the mouth, muscle cramps, or spasms after parathyroid surgery may indicate low calcium and should also be assessed promptly.
Arrange routine follow-up if fatigue, thirst, constipation, bone pain, or concentration problems are worsening.
Keep planned blood, bone density, and kidney checks even when you have no symptoms.
Every sign above is quoted from the sofidex article on Parathyroid adenoma. If you are not sure, err upward — it is always reasonable to be checked.