Hi...Can understand your concern...As per your query about tooth infection which is being treated for about 2.5 months..I wish to have details like your age and weather any xray of the infected tooth was done?Which antibiotics and pain killer you have been prescribed? lf you are an otherwise healthy person ,it seems that the antibiotics which you re being prescribed is not providing effective coverage .you are also not able to open your mouth because of inflammation in involved area of the infection may have spread a little more and due to proliferating bacteriae... There is need to change the antibiotics along with some strong analgesic like tramadol with serratiopeptidase to reduce the pain and inflammation...Also after the infection subsides you need to take its appropriate procedure like root canal or extraction etc for a permanent remedy. Infections some times may traverse the tissue spaces in oral cavity and can cause much serious condition and sometimes it can also reach bloodstream and cause more serious conditions so appropriate treatment is needed soon. I suggest to consult your dentist again and ask him for change in medications and dosage for a effective treatment.Also if you are not totally satisfied with him you can go to ER.or an oral and maxillofacial surgeon who will evaluate and diagnose the condition properly.I hope the information helps you.You are welcome to have any further query...Take care.