As evident from the photos provided by you, you are already undergoing orthodontic treatment. Anyhow your forcible clenching of teeth does not much affect the pattern of your jaw or alignment of your teeth except injuring your muscles of mastication and other allied muscle(s) and even the TM(jaw) joint to some extent. So stop any unnecessary habits immediately and follow the advice of your doctor (orthodontist). It seems you might have spasm in the muscle(s) or related pain in muscles/ joint which may be relieved my warm dry compress on the TM joint/ ear region on both sides. Also you may take some muscle relaxant medicines as advised by your doctor.

Hello Sir, I would advise you to consult with your orthodontist about your condition since during the course of treatment you might feel discomfort since it’s a myofunctional appliance( it takes support of your muscles to move your teeth). Inform him about your tmj issues.

Well,as you are undergoing orthodontic treatment,you have to wait till it finishes after which you may be needing a night guard to overcome grinding problem.Moreover this habit doesn't solve the problem of bite correction,so better to quit it asap.Also take as soft diet for few days.See an oral medicine person.

Usually the TMJ joint can be affected due to long standing habit of clenching. Since you did not do it for a long period you should be fine