Third Eye of The Moon

On the brink of night is when you must cast this spell if, in anyway you are disturbed during the casting time then the spell stops. Slowly as the night drapes over you and any watchers you begin to feel a wierd felling in the middle of your forehead. As the night goes on it becomes worse and worse but if you react the spell stops. Right when the moon hits the top of the sky a opening begins to form in the middle of your forehead slowly realizing a third eye. This third eye will continue to open the rest of the night intil it his day now it is over and you have a third eye. What this third eye allows is the use of spells from another class at your level each of these spells including cantrips can only be used once per long rest, additionally when you use one all go away intil another long rest. Finally this allows you to change the class that you have chosen a total of three times.