I'm 12 weeks pregnant and have impetigo herpetiformis. i have also been diagnosed with hypothroidism for years.could it be hypoparathyroidsim inistead?

Both are possible: Impetigo herpetiformis or pustular psoriasis of pregnancy can be associated with calcium changes in the blood tests. Usually there is an elevated serum calcium in this condition. The thyroid blood test are accurate and are a separate problem.

Parathyroid : Parathyroid dysfunction is typically not related to the thyroid dysfunction. Usually, a parathyroid dysfunction is diagnosed after incidental calcium abnormality detection in the blood (either low - hypoparathyroidism, or high - hyperparathyroidism).

Unlikely: Despite the similar names, hypothyroidism and hypoparathyroidism are entirely separate entities. Patients with hypothyroidism experience a slowing of metabolism, while patients with the latter develop low calcium levels and possible "pins and needles" sensations around the lips and in the fingers and toes. It is straightforward for a doctor to distinguish between the two based on labs and symptoms.