hi and welcome,
After reading your history i suspect you have developed infection on the left side of the face involving neck jaw and ear.
It could be tooth related infection or abscess formation that often gives fowl smell in the mouth , periodontal abscess
even spread to the spaces of neck and radiate pain to ear and the side of the jaw.
i would suggest you to get an OPG radiograph done which will confirm the whether the infection is associated with lower jaw or upper jaw and maxillary sinus
Visit a doctor and get clinical examination done to confirm.
mean while you have start with antibiotic Augmentin
625 mg along with painkillers 2 times daily till you see a doctor.