That's going to depend on many factors. But, typically, many people are diagnosed with PsA only after the onset of a bad flare, and as such, they've not been on any DMARDs whatsoever. In this case, a flare can last quite a long while, but will generally begin subsiding within weeks of being prescribed either Prednisone, Mobic, or some sort of DMARD. My best advice to you, aside from listening to your rheumatologist, is to immediately begin to intensively regiment your lifestyle and diet. If you use alcohol and/or tobacco, you will need to stop. Additionally, many of us with PsA have seen benefits simply giving up highly processed foods, sugar, and red meat. Eat lots of fresh vegetables, or frozen if that's more budget friendly for you. These kinds of lifestyle changes may not affect any immediate change (except for giving up tobacco and alcohol), but they will, over time, help a great deal.