According to the USDA, heavy cream can be stored in the refrigerator (opened or unopened) for up to a month. 1  This assumes that it has been kept at a constant refrigerator temperature and not left out on the counter for stretches of time. Discard any cream with mold or an off odor.
However, one of the most common causes of lockjaw, as already mentioned, is TMJ disorder. TMJ disorder refers to a syndrome that affects the temporomandibular joint, commonly called the TMJ, which connects the jaw with the bottom of the skull.
Lockjaw from TMJ is a function of the muscles of the jaw being so tight that they either pull the joint out of alignment, or they are so tight that as you open your mouth, they seize/spasm and lock the jaw in place for some length of time.