Sinus cavity has been exposed from tooth extraction. high fever for 5 days, sore throat.

High fever: With an exposed sinus cavity and a high fever, i would pay an immediate visit to the er for an evaluation and further treatment.

See the dentist/OMS.: An infection appears to be present and go back to the doc who took it out. If unavailable, find an oral maxillofacial surgeon. Sometimes an additional surgical procedure is required.

Tooth extraction: It is difficult to diagnose the actual problem. it may be due to an upper respiratory viral infection, an infection of the tooth extraction site, or a sinus infection, or all of the above at once. The question is how does the doc know that the sinus was exposed? By xray, by "feeling" for the sockets with a probe, or just "guessing". The proper treatment requires a bit more diagnostic info.

See oral surgeon: Sinus communication is not uncommon complication when extracting upper molars. You should see an oral surgeon. The goal is to surgically obtain primary closure and eliminate infection. Good luck.