I have been diagnosed with having "desquamative interstitial pneumonia" or dip which is a lung disease. can this disease be reversed? can it be fatal?

It is a bad disease: Dip can sometimes be reversed successfuly with the use of steroids...So some people do recover. But others can end up as respiratory criples requiring lung trnasplantation as the last resort for survival.

Check with your doc: Dip is relatively benign . However, there may be another diagnosis such as nsip, ipf, rbild, cop, aip, cep, uip or lip the prognosis of dip is generally good. Most patients improve with smoking cessation and corticosteroids. The overall survival is about 70% after 10 years. Your doctor may start you on Prednisone 1 mg/kg/day and you will hopefully respond. Dip is certainly better than ipf.