I am sorry to hear that you have had problems with trembling when smiling or laughing and that you are unable to lift your cheek which has resulted in you trying not to smile, and that you are worried about what might be wrong with you. I am happy to give you some of my initial thoughts about what might be going on, but ultimately I am going to recommend that you make an appointment with an ENT (Ear Nose Throat) physician, aka otolaryngologist
. they will be able to take more of a history and examine you which I am not able to do in this setting. I'm not totally sure that you mean when you say that your face is 'trembling', but it makes my think of synkinesis. For instance, if you had Bells palsy
, a disorder characterized by unilateral facial never immobility without any obvious etiology, sometimes when there is nerve regeneration, the muscles that any given nerve are re-innervating may have a crossed signal. This means that when your brain is telling one particular muscle on your face to contract, the signal gets mixed up and there is partial firing of other muscles (termed synkinesis). I am not sure if this is actually what is going on in your case without being able to get more of a history, or examine you, but this is my initial thought with what you have given me. An ENT will be able to tell you if this is in fact what is going on. Best of luck.