I really can't offer too much advice since I consider myself a newbie at this as well.
But I would forgot the misting all together. It creates moldy spots on flowers (like what you have) and could create crown rot if the water sits in the leaf crevices too long. And it does virtually nothing to raise humidity. I only mist if I have aerial roots and then I only mist the roots and not the plant. If it was my plant I would repot it right away. The roots may be perfectly fine but I would still want to see whats going on under that moss. Watering once a week may be too much if the mix is broken down so checking the situation out would be beneficial. Just my
