I tried Retin-A cream (the one used for acne)... didnt work. Im currently using clobetasol ointment with SSA...so far, it effectively keeps my KP under control.

Clobetasol is a corticosteroid though, there are dangers to using it long-term especially on large areas of skin. I've also had huge success keeping KP under control with a corticosteroid/salicylic ointment (Diprosalic). It works FAST, as in within a few days. But as with anything, the results are temporary and the KP comes back soon after I stop using it. The dangers of topical steroids have kept me away from the Diprosalic in the past few years. I think it might be best to use corticosteroids just until the KP is under control, and then maintain the results with exfoliating agents like salicylic acid and glycolic acid. My favorite product that combines these two ingredients is Philosophy Soul Owner, a foot cream.

Tretinoin has a keratolytic (exfoliating) effect so it probably would help the KP. The downside is that it can be expensive (in the US) if you are treating a large area. It can also make your skin photosensitive so you need a reliable sunscreen. Tretinoin is an OTC product here (am not in the US), and I have access to inexpensive forms of it. I've tried a tretinoin solution to treat the KP on my upper arms. It caused the skin to peel repeatedly, then the peeling tapered off. VERY good results with this. Again, like the corticosteroid, I would suggest tretinoin as a "jumpstart" to get smooth skin, then maintain results with a glycolic/salicylic product.

I've been using tretinoin on my face and neck for the anti-aging benefits and I love what it has done for my skin.