Do I still have a chance to join even with my "medical" history?

So years ago I was told I had psoriasis, to which I've heard is one of the hardest medical waivers to receive. However it has always just been a very small patch on my head and is rarely ever a problem. It almost never shows up. But that being said, im still worried if they see it even a little or find a medical record stating it that all my chances are gone. So is it really that bad or do I still have a considerable chance to join?