Can teething cause fever for my 7 mounth baby?

Yes. Fever is a common "side effect" of teething in infants. Monitor the temperature and call your doctor if it gets above 102, or if your infant has other symptoms (cough, runny nose, congestion, etc.) as there can be other causes of fever as well.
Not Usually. There is usually some underlying cause for the fever. Teething alone will not cause a fever. If that was the case many children would be feverish for months on end as new teeth continually erupted.