Do NOT mist it. That is part of its problem, I'd bet. Misting tends to do nothing for the plant other than help keep the soil soggy.
Also, there is a tendency for beginners to want to "do" something to their trees constantly. That is mostly a death sentence for the tree. There is no reason for all the fuss. Trees can do fine on their own, as long as they get adequate water and light--Adequate water means watering when the tree needs it, not according to your schedule.It should REMAIN IN ONE PLACE for the remainder of the summer and early fall. Trees have roots, which means they are NOT ambulatory and not used to moving aroumd. Moving them indoors and outdoors constantly forces them to re-adjust to local microclimates with every move. That stresses them out and forces them to use a lot of energy and reserves which can wind up being fatal.
Watering is one of the hardest things to master in bonsai. Soil should approach dryness (or even dry out a bit in the case of B. ficus) before more water is added. This can be monitored with the "chop stick" method --do a search on the term here.