Hello, No brain leakage should occur from a root canal. You may have a fistula that has made a pathway into your sinus. This would allow nasal drainage of the infection and may appear as a nasal liquid. Antiobiotics such as amoxicillin should be prescribed to hel this to resolve. If there is a commuication into the sinus this needs time to heal and often will on it s own once the source of the infection is removed. Do not create stress or blow your nose. Limit bending. Gently wipe your nose. Decongestants and saline nasal spray may be helpful. Anti-inflammatory medication such as the antihistamine Benadryl is recommended. Other anti-inflammatory medications include ibufropen or acetaminophen. Consult with your dentist and inform your dentist of this drainage. Follow all instructions and take any prescription medications indicated. Root canals usually require more than one visit to complete. X-rays can be taken to evaluate the root for any treatment complications. Make sure you have completed the procedure. Thank you for your inquiry. I hope this has been helpful and you are not overly worried. I feel this will not be difficult to resolve.