First and foremost, you need a proper diagnosis from a dermatologist. There could be a myriad of other possibilities outside of psoriasis and treatment may vary.

That being said, if you are having positive results with the steroid topical, keep using it. When the lesions go away after use, that's good. But, you have to maintain use even after they're gone, just not as frequently.

Everybody and their grandmother has a diet trick for psoriasis. They all work in their own way, just not the same for every person. I've heard about carb/citrus/gluten/wheat/veggie/vegan/etc... If you find something that you feel works for you, great. The general concensus with it is a healthy diet reduced stress and inflammation, hence better, clearer skin.

Sunlight is your buddy. So is swimming (pool or ocean). The salt and chlorine help dry up the patches and the sun (bear with me) cooks them away. Okay, it doesn't cook them away, but it does help you produce D3 which is imperative to skin health. For me, the sun slowly melts them away. I get darker, they get lighter and eventually fade into nonexistence. Well, until the weather changes and they come back. Tanning booths can garner the same results (over time) if it's easier for you. Let the shop owner know you are using their booths to treat psoriasis and they can guide you to the appropriate lamps.

Psoriasis is a forever condition. The skin lesions are a side effect of an autoimmune disorder. Because of this you need to be properly diagnosed. Also, using certain medications in your armpit is not recommended due to a large group of lymph nodes being right there.

As for choosing between meds/lotion/deodorant, you just have to find the best timing. Ointment is probably best before bed (less chance of rubbing it off), deodorant in the morning and lotion in the afternoon. Play with it and see what works best for you.

Good luck with everything! The biggest trigger is stress, so try no to stress out about not stressing out. That parts the hardest.