HI, thanks for using healthcare magic It is definitely possible that you have a sinus infection involving the left side of the face. Most infections are viral though bacterial and less commonly, fungal infections are possible and occur as well. A bacterial infection would cause a prolonged fever along with a smelly discharge. Treatment for a sinus infection involves the use of anti histamines and decongestants (both oral and topical) eg zyrtec d, allegra d, claritine d, benadryl d. Example of topical decongestants include otrivine and normal saline A pain killer such as ibuprofen or paracetamol can be used to help the headache. If the symptoms do not improve or they are severe then you should see your doctor for assistance I hope this helps