I have chronic sinusitis and have dabbled with Neti pots and other similar devices. I have more or less stopped using them because while they do wash out a lot of the gunk and provide some short-term relief, I also feel like some liquid gets trapped up there and that only makes things worse a couple of hours later. It will also give me some minor problems with hearing and getting the pressure in my ears to equalize.
If you have swelling and inflammation in your nostrils, I would not use a neti pot. Tackle that first.
If you need to, don't be afraid of taking an over-the-counter decongestant (with pseudophedrine) every once in a while. It feels like cheating but it does help.