After i got my wisdom teeth removed, my jaw is not opening.what should i do?

It's important.: ... To diagnose the reason behind your inability to open your mouth after wisdom teeth extraction. Normally the reason behind such thing is the usual inflammation of the surgical site and your jaw joints for few days... Especially if you have taken all of your four wisdom teeth out together. Contact the dentist, or oral surgeon who did the procedure for you and let them know.

Muscle spasm: The jaw lock usually happens post operative either from muscle spasm in the cheeck muscle from the injection site of the anesthetic agent, or from infection from the extraction site that lead to muscle infection, wether the reason is traumatic from needle or infectious from the surgery, you need to go back to your dentist for evaluation and subsequent treatment

Additionally: Dr jamie is correct. Additionally can be from displaced disc in jaw joint. Your oral and maxillofacial surgeon specialist will know what to do.