Hello and welcome to hcm,
From the details provided,its not clear that what was your concern for dental surgesy.
Since there is terrible odour,chance of sinus infection
Take complete course of antibiotics.
Maintain good oral hygiene
Smell will gradually subside once the infection relieves.
Also consult a physician regarding the stomach-ache.
Get your entire mouth examined and get all your decayed teeth restored and scaling done.
Grossly decayed teeth has to be removed.
Also check whether wisdom tooth is impacted ,and if impacted either operculectomy/extraction of tooth has to be done.