treatment of your condition depends on diagnosis of nasal condition you are suffering from. nasal block can be due to many reasons such as deviated nasal septum, allergic rhinitis, nasal polyps. turbinate hypertrophy once the diagnosis is made treatment can be planned. coming to nasal sprays, decongestant nasal sprays such as oxymetazoline or xylometazoline should not used for long term as they may cause injury to nasal mucosa. but steroid nasal sprays are safe and can be used for years without much of problems kindly consult nearby ENT specialist