Year long runny nose hello, ever since I was a kid (13 yrs old) I've had constant dry mucus coming out mostly from my left nostril. As I got older, it started to become more moist and now (19 yrs old) it's kind of like a sinus thing where not much wou

It . It is important to see an ENT in this case to investigate the root cause of your problem. Discharge from one side of the nose, if watery and not thick like you describe is suspect for cerebrospinal fluid leak (through tiny cracks in the floor of the nose which is the floor of the brain case). A cat scan of the sinuses sometimes is helpful in locating a polyp or other inflammatory causes. Finally form a treatment perspective, there are surgical procedures where medical treatment fails that may be offered including a turbinectomy, a procedure in which the nasal turbinates, structures that provide moisture and heat to the air we breathe through the nose may be shrunken or partially removed in order to dry up the nose and also reduce nasal congestion.
A . A visit with an otolaryngologist or ENT doctor would allow for a full assessment of your nasal symptoms to see what could be done. A sinus ct scan would probably be very helpful at this stage to further examine your sinuses themselves. It may also be reasonable to consider a steroid nasal spray trial for 2-3 months to see if that helps at all. There are a few other oral medications, besides the anti-histamines that you mentioned, that could be considered also. One example is montelukast (singulair).