Dark Spots on my face

I have some dark spots on my face that I got once when I spent the day out in the sun and didn't have enough protection. ( I dread that day every time I look in the mirror). I have been to a couple dermatologists that have prescribed me Hydroquinone which made my skin very red so I stopped using it. Is there any other remedy that might help the dis-coloration disappear once and for all?
Also, I always use 60 spf now on my face, however when its a hot day outside, I feel my skin getting hot and burning in the area where the spots are. Does anyone know why this happens?