What Is The Cause Of Jaw Getting Locked?

hi dr. we had sex with my partner last night. it so embarrasing but i did bj and suddendly my jaw just locked. i couldnt open my mouth tha big what shall i do. it also happened to me before while i was brushing my teeth but it just came back but now its still here since from last night. what eshall i do. pls help me dr