I am brazilian too, welcome to DV
I understand your worries, there are no cases where it is reported that a "lucid dream" has caused any damage at any level, be it psychological or physiological. Your mind will behave the same as before but it can change the way you see life, well for me totally changed. Your non-lucids dreams will be the same as always, is possible that you realize that you are dreaming with no intention sometimes but if you just stop thinking about how it's a dream you will lost the lucidy and the dream will be a non-lucid dream again. Don't worry about it, lucid dreaming is safe.