Does myexedema occur progressively or is it acute?

Myxedema: Myxedema is a form of cutaneous and dermal swelling due to deposition of connective tissue material (like glycosaminoglycans, hyaluronic acid, and other mucopolysaccharides) as in forms of hypothyroidism and graves' disease (pretibial myxedema) more commonly in women and is almost always chronic and progressive rather than acute.

Progressive: Myexedema due to low levels of thyroid hormone , do not appear over night , is progressive disease , after start of treatments will subside progressively

Progressive : Myxedema is severe, progressive hypothyroidism, or low level of thyroid hormone in the system. If it's severe enough, it can result in loss of brain function, or coma. Earlier symptoms include fatigue, lethargy, depression, cold intolerance, dry skin, weight gain, constipation, & headaches, etc.